Instructions
Purchase only sub-machine guns and pistols. Assault and sniper rifles deal more damage and require less successful shots to score a kill. By buying a weaker weapon with a similar rate of fire, such as a sub-machine gun or a pistol, you will have to land more successful shots to kill someone. Forcing yourself to perform better by using a weaker weapon will improve your aim, and those skills will transcend beyond the weaker weapons and into assault and sniper rifles.
Do not reload your weapon. Not having a full magazine in your weapon will force you to conserve your rounds and make them count. This will increase the difficulty of playing the game, but if you can get more kills than deaths when you are at a disadvantage, you will be able to perform better when everything is even.
Play with bots. Start a private server on your own and work your way from easy bots to the hardest ones. Set goals for yourself in each round. For example, if you are planning on being a sniper, do not allow yourself to increase the difficulty of your bots until you can score a certain amount of headshots in one round. If you are playing with an assault rifle, do not increase the difficulty of your bots until you can score two or three kills for every death.
Play on servers with friendly fire turned on. When friendly fire is turned on, your shots will inflict damage on everyone, including your team mates. This will teach you not to randomly spray your rounds everywhere and be more cautious with your guns.