Here are some of my general tips to doing better on the battlefield:
1) Communicate: It's important in any online team game to communicate and COD4 is no different. The more you talk, the more your teammates will talk. Call out enemy positions, tell your teammates what you are planning, etc. Communicating not ony will make you a better player but will increase the team's chance of winning.
2) Find your niche in a team: find out what you are good at by experimenting with different weapons and using them in different ways. Once you feel you are comfortable with something, practice with it.
3) Know where your enemies are and where they are spawning from: This is key in a game like COD4 where the spawns switch based on the players' location. You always want to know where your enemy is so you can keep them in front of you or create successful flanks.
4) Work on your reaction time: Usually in COD4, whoever pulls the trigger first gets the kill. Practice pulling the trigger quickly.
5) Work on accuracy: Accuracy is another key of the game. I recommend usig the red dot perk if you are having trouble with your accuracy, as it can help you pinpoint your aim.
6) Reload during breaks in the action: COD4 is realistic enough so that you can't just spray and pray to get kills. You need to time your reloading so that after one or two kills, you find a safe spot to reload.
7) Tap the trigger: Tapping the trigger helps your accuracy and conserves ammo. Especially for long distance shots, it's better if you burst your ammo, and in COD4 it's easier than ever to do that. There's no special button you need to press, just tap the trigger button.
8) Use cover wisely: Too many people run blindly around COD4. They get picked. Movement is necessary in the game, but always ask yourself if you are opening youself up to an easy shot.
9) Outsmart you enemy: Go against conventional wisdom. Doing so will give you the element of suprise.
10) Use the SPRINT button sparingly. Sprinting is awesome if you need to get somewhere fast, but it slows down your reaction time. I don't know why that is, but it's just how the game mechanics are. The player actually has to stop running to be able to pull out his gun in time. In reality, it takes only a split second, but that's all the other guy needs to split you.
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Well that's all for now, so hope this info is useful.
