While we all know the basics of practice makes perfect have been proven right on so many occasions, the frustrations of getting to perfection can be endless.
Let's first talk about the factors of getting "Perfect aim" or at the very least, very close to it.
Firstly you need to be quick with reacting.
Reactions determine who gets the first shot in and that usually determines the winner as well in most scenarios.
So step one is to train your reaction time and you can do so with the below links:
https://www.humanbenchmark.com/tests/reactiontime
and
http://www.bbc.co.uk/science/humanbody/sleep/sheep/
Trying to get solid top scores is also good as you can see where you are compared to others who do the same practice.
Now we have to move on to the movement, it also needs to be fast and yet steady if your going to land the shot.
Most FPS players use a mouse with low DPI and then try and cover the entire mouse pad when moving their hand or arm to ensure a steady aim while being able to move at a good pace to catch the target.
A good practice is to put your mouse in the center of your mouse pad and when moving it all thr way to the left or right you need to be able to make a full 360 degree turn.
This lets is usually the most optimal for FPS games.
Now onto the good stuff, shooting training.
So once you have the setup looking good on turn rate you can try the below sites for aim training:
http://www.albinoblacksheep.com/flash/shoot
and
http://www.aimbooster.com/
using these sites everyday for a few minutes to an hour or two (Depending on how well you'er doing in FPS games), you should see an improvement in your game play.
Quick tip;
Another thing to note is that you cannot let yourself get distracted from your target.
Try focusing on one at a time, we all know that if there's more players against you, then it becomes difficult, but letting the one player live because you were trying to focus all of them together makes the other guys someone else on your teams problem now and might cost you dearly for it.
Please feel free to follow me for more information and guides to improve your game play!