- Move evasively
Since you have to keep moving to avoid making yourself a target, you'd better not move predictably, either. The worst thing you can do when charging is to make a direct beeline for your target; all he has to do is line up on you and keep shooting. Dodging randomly makes it harder to draw a bead on you, and hopping about makes it hard to get constant, easy splash damage from rockets and such. Keep moving, and keep dodging.
Moving evasively -- dodging and jumping at random -- makes you a much harder target to hit.
- Exploit cover
Exploiting cover is one of the most fundamental skills for even a novice player. If you're hiding behind something, the enemy can't hit you, even if they know exactly where you are. When making a charge, move from cover to cover to minimize your exposure to enemy fire -- and do so when making a retreat as well.
Use cover. Constantly.
- Use mouse look
Instead of using the keypad to look around, you should be using the mouse. This allows easy, intuitive, and -- most importantly -- quick viewing. Mouse look allows you to respond instantly to threats; every experienced first person shooter player uses mouse look. Once this is done, you'll find that for basic movement you only need a cluster of keys mapping to forward, backward, strafe left, and strafe right. (You won't need turn keys anymore, since you'll be using the mouse for that.) Getting used to mouse look at first is rather awkward, but very quickly you'll find yourself getting used to it.
Enable mouse look. You won't regret it.
- Turn up your mouse sensitivity
Higher mouse sensitivity means greater movement of your view with less movement of the mouse -- moving the mouse takes time. This is greatly helpful in fast-paced, first-person shooter games. High mouse sensitivity means that you can make sharp turns very quickly, and respond to attacks even faster.
Turn up your mouse sensitivity as high as you can stand it, but make sure that it's not turned up so high you can't aim accurately.
- Configure your key mapping to your liking
With mouse look your free hand should rest on the keyboard. Your hand should rest on a cluster of move keys -- forward, backward, sidestep left, and sidestep right -- and surrounding those keys should be the keys, configured to your liking, for selecting weapons, maneuvering, and so on. The most important thing about choosing a key mapping is that it suits you -- if you don't feel comfortable with a mapping then it won't help you.
Configure the keyboard commands to you liking so that all the keys you need are in easy reach of your keyboard hand.
- Strafe around corners
Always strafe -- sidestep -- around corners so that you can keep your face to any potential threats. Don't walk into an intersection and then turn -- that leaves you wide open to an attack before you can even see where it's coming from.
A fluid corner strafe motion will become one of your greatest assets. Soon you won't even realize you're doing it.
- Learn to look obliquely while running
A skill that you can absolutely not do without in first person shooters is (with mouse look) to look in a direction you're not in. When using sidestepping, you can look to your sides -- or even behind you -- while running. Important also is the ability to switch back and forth, between moving and looking forward, moving forward but looking obliquely, and back to moving and looking in the same direction. This is an essential tactic; it allows you to peek down corridors you're passing by, or look behind you, while still going where you want. Particularly while retreating, being able to make a break for it, turn around and keep up suppressive fire while still running away from the battleground.
Learn how to look in different directions (to each side and behind) while running in a given direction, and be able to switch back and forth rapidly.
- Learn how to make quick reverses
Being able to quickly make a 180 degree turn can save your life -- you will frequently find yourself under surprise attack from the rear. Players will attack you from all sides -- and, indeed, some make a concerted effort to sneak up on their victims.
Be prepared to make a lot of quick reverses. You'll need them.
- Learn how to make fast but accurate snapshots
A "snapshot" is a shot with any ranged weapon that is made very quickly. When retreating, for instance, one might make a quick reverse, a snapshot at one's pursuer, and then continue the retreat. A snapshot is more frequently used as suppressive fire, rather than a specific attempt to do damage -- that is, when making snapshots you want to try to keep someone off your back, or keep an avenue of retreat open, but don't have the time to line up for an accurate shot. Snapshots are an effective way of making your opponents know that you're still dangerous.
Practice taking quick snapshots -- turn, line up, fire, and then turn back.
- Keep an eye on your health and armor
It seems obvious, but it's still so important it's worth mentioning: Keep an eye on your health and armor. Health and armor typically start at 100 each. Health indicates how alive you are; when it reaches zero, you're dead. Armor helps (in some circumstances) take some of the damage away from health, so a heavily-armored player taking fire is more likely to lose damage than health (depending on where the shots land).
Watch your health carefully; if it drops too low, retreat. Be sure to talk up on armor; more armor means you can stay in the fight longer.
- Cautiously enter vulnerable areas
When in the thick of things, charging into an open area where you will be vulnerable to enemy fire is a bad idea. That doesn't mean you have to creep along corridors like a frightened child, but being cautious about bursting into areas that put you at risk is always a good idea. Instead of running into a potentially dangerous area, stop at the threshold and stroll casually out, staying near cover, to see if anyone is obviously sniping.
When about to enter an open, vulnerable area, pause at the threshold, peek around for a second or two, and then continue on.
- Learn to determine where shooters are from their gunfire
Learning to recognize the behavior of gunfire of all types will help you determine easily where your enemies are -- at least the general area. Bullet rounds hitting the wall near you, or a rocket trail or railgun blast will help pinpoint your enemies. Even a grenade lobbed in your direction is instructive.
If you can identify where shooters are without being in direct line-of-sight, you will have an advantage in mounting a counterattack.
- Use suppressive fire
Even in games with unrealistic weapons, suppressive fire is essential among first person shooters. "Suppressive fire" is a military term which means fire which is not intended specifically to kill the enemy, but rather to get him to stop shooting at you. In movies when the hero shouts, "Cover me!" and his cohorts at arms let loose on the enemy's position even though the enemy is hiding, that is suppressive fire. The goal of suppressive fire is: Keep the enemy occupied so that he can't fire back, or at least has to think about things other than killing you for a few moments; if he's not shooting at you, he can't kill you. Suppressive fire is useful for covering a corridor which you think players might be coming out of, or, most effectively, to cover a retreat.
Suppressive fire can be your friend. Sometimes the best tactic is to shoot not to kill, but rather to keep them from shooting back.
- Be stealthy when you need to
When you're being pursued or are pursuing someone and don't want them to know you're there, be stealthy. Walk instead of run; you will not make the sound of footsteps. Avoid picking up weapons and items and interacting with the environment in noisy ways unless you absolutely have to.
If you want to keep quiet, avoid picking up items and interacting with the environment.
- Always leave yourself a line of retreat
When engaging the enemy, always keep in mind which way you'll be running if things get too hot -- usually this should be the way you came in. If find yourself under unexpected fire or a deadly crossfire, immediately start a full retreat through the safest path, annihilating anyone in your way and using suppressive fire to cover your tracks.
Always leave yourself a line of retreat. If it gets cut, immediately start to find another way out.
- Pay close attention to sound
In first person shooters, things make sounds -- gunfire, picking objects, players interacting with the map, you name it. Sound is also positional; with stereo speakers or headphones, you can easily tell whether the sound is on your left and right (but not so much whether it's above or below). The distinctive noises associated with different actions, items and powerups should be carefully weighed against your knowledge of the map; if you hear the sound of a ladder, for instance, and you know the only ladder near you is below you, then you know exactly where the enemy is. When players are being stealthy, their footsteps do not make sound, so one must be more careful.
Recognize and act on the noises players make in adjacent rooms; being able to act on this information will make you a much deadlier opponent.
- Know the maps
Knowing the maps you're playing is essential for any number of reasons -- you know the lines of attack and retreat, you know where the important weapons and items are, where the artifacts are on the map that will cause key noises, if an enemy runs into one passage where he's likely to come out, and so on.
If you know the arena you're playing in very well, you'll have a powerful advantage over everybody that doesn't.
- Learn to head people off at the pass
If you know well the map that you're playing in, you can know when other players are running into a dead end, or a room with only one other exit, and so on. Knowing this can allow you to make tactical decisions to pursue or "head someone off at the pass," or to anticipate their next move and position yourself to pounce on them when they get there. Being able to do this effectively when it counts is a skill that will leave inexperienced players completely and utterly baffled.
Knowing the arena allows you to head other players off at the past by anticipating their moves based on where you see them going.
- Turn off autoswitch weapons
Most first person shooters by default have "autoswitch weapons" on -- that is, when you pick up a weapon for the first time, you will automatically switch to it. This seems like a good idea at first -- it gets you familiar with new weapons as soon as you encounter them -- but if an autoswitch occurs in the middle of combat, this can spell disaster. Games which have this feature, however, have an option to turn it off.
You're better off turning autoswitch weapons off so you don't get any weapon switch surprises in combat.
- Watch your back
In a fast-paced combat arena, enemies will come at you from all sides. Always be prepared to be flanked; frequently watch your back, making quick reverses to catch anyone sneaking up on you. This is particularly important when you're beginning an assault, since maintaining a line of retreat is essential.
Always watch your six.
- Retreat when in trouble
Many players, particularly in deathmatch-style games, never retreat -- they fight to the death, even when the odds are hopeless. There is no shame in pulling back when a battle is not going well -- in fact, it's the sign of a good player. Especially in survivor-style games where death means you're out until the next round, running headlong into combat is generally unwise.
Always leave yourself an avenue of retreat, so you can pull back if things get ugly.
- Learn to steer in midair
Midair steering -- being able to deviate from a simple, freefall path -- is of vital importance. It's particularly true on low gravity servers, but even in normal maps with normal gravity, midair steering can allow you to alter your path even with simple jumps so that you're not an easy sniper target, and can help guide yourself to safe areas below and can mean the difference between life and death.
Midair maneuvering may seem bizarre but it is a very valuable skill.
- Watch out for friendly fire (friendly fire)
In games where friendly fire is enabled, watch your targets! Your teammates are counting on you to be discriminating -- team-based play is very different from a free-for-all.
Watch your fire! Injuring your own teammates is a sure-fire way to get unappreciated right quick.
- Keep track of the number of enemies remaining (survivor-style)
In survivor-style games, you can find out the number of enemies still alive during a round by checking the multiplayer stats screen. This information is vital -- pursuing one enemy involves quite different tactics than hunting multiple bogies. In particular, if you know there's only one enemy left, and you know the general area where he is, you can't get ambushed so you can choose different tactics to hunt him down. Note that keeping track of remaining friendlies is useful too -- when you're the only member of your team left in a friendly fire game, you know anything that moves is the enemy.
When the number of enemies drops to only a handful or just one, switch from search-and-destroy tactics to hunting tactics.
- Get a feel for the skills of your enemies and prioritize
When you've been playing on a server for a little while, you get an easy feel for the skills of your opponents -- some are novice, some intermediate, and some are expert. Being able to recognize which enemy you're engaging -- either by their choice of model or the heads-up display annotations -- will allow you to prioritize your attacks. If the enemy force consists, for instance, of one relatively skilled player and several green players, you will want to engage and take out the hard target first, and then take your time eliminating the remainder. Doing this allows you (and perhaps your team) to take out the hard targets first while you still have the strongest force, maximizing your chances for success.
Take out the hard enemies first, then mop up the rest.
- Set resolution to be a tradeoff between detail and framerate
The resolution of the screen that you choose will have an effect on gameplay. Too low and it will be hard to see what's going on; too high and your framerate will suffer. Above all else, having a high framerate is essential for smooth gameplay, particularly on a fast-paced multiplayer server.
Choose a resolution that gives you a good tradeoff between framerate and detail.
- Engage enemies on your own terms, not theirs
You should be picking and choosing your battles, not your enemy. If you are always reacting instead of acting, you will be at a constant disadvantage to a better-equipped, more prepared enemy. Instead, take the initiative and start attacks where you have the upper hand.
Act, don't react.
- Assist your teammates (team-based)
Does it need to be said? Help your teammates. Follow them when appropriate, move in squads, assist your team when you fall under fire. The worst thing that you can be in a team-based game is a "hot dogger," a player who is just out for number one.
You and your teammates are in this together. If you don't help each other you will fall to a more organized foe.
- Don't bunch up (team-based)
When you're in a team-based game and moving together, bunching up -- getting too close to each other -- can cause serious problems for your team for several reasons. First, if you are close together area-effect fire such as grenades will potentially affect all of you, rather than only one or a few. Second, and probably more importantly, bunching up restricts free movement of each member of the squad. In particular, the team members at the forefront of the attack will occasionally have to fall back or fully retreat; if his teammates are all bunched up behind him, he will have nowhere to go and will likely be killed. If there is sufficient spacing between his teammates, he will be able to retreat and the squad can regroup.
Don't get too close together, or you'll sustain heavier losses and be unable to pull back when it counts.
- Don't hesitate at entryways with teammates behind you (team-based)
When moving with a squad, you will frequently come upon chokepoints where only one player can move through at a time. These chokepoints can be death traps if you don't handle them properly. In free-for-all play, typically a player will hesitate at the chokepoint, using it as cover. This doesn't work as well for team-based play; when doing so, this can cause bunching up of the teammates behind you, but more importantly, you're not using the primary asset that your squad has -- firepower. If you're on point and are preventing your teammates from moving through, only you are exposed to enemy fire, and only you can fire back. That means that you are more likely to be killed. Instead, when there are teammates behind you, move through the chokepoint to allow more of your squad to get through the chokepoint.
Don't stop at chokepoints when your men are waiting behind you; allow more of your team through so that there will be more return fire and more targets for the enemy to hit.
- Use macros to say frequent things (team-based)
In team-based games where you're communicating with your teammates, you will frequently find yourself saying things like "clear" or "affirmative" or "move out." For these kinds of commands, it is helpful to bind keys to these short commands -- or, if the game that you're supporting has some kind of radio support, that is preferred (since it gives an audio cue as well as the text of the message).
As with all things, macros can be overused -- don't flood or spam with them; use them to communicate, not annoy.