play vs pros,dont play with people that are 100%noobs or u wont get better.
get use to one or two guns.
learn how to burst shoot.
get an AWM,then learn how to quick scope.
use a head set and walk alot.
get a gun from BL.
or,get someone to train u ingame.
Never go into Rookie server.
Play in the server that you have the lowest ping.
Check the comfort of your mouse and your keyboard.
Set the shortcuts for easy use.
Watch some videos giving tips n tricks or watch frag videos paying attention to how they are moving and how they are aiming.
Lower your sensitivity so you can get a clean shot.
If you do all of those,that's just the matter of time.Wait for the day you pwn alot