Pretty sure the mlg geezers use a low setting anyway but it's player specific. It takes time to get used to a new sensitivity that's why I said do it gradually. 1 step at a time until you're happy.
when you up it you will have to adjust. the higher you go the less accurate you will be. you just need time to adjust
Persistence is the key to my game, just keep executing your game plan, and most of the time it will start to come together!
-Learn the maps and the routes people always take.
-figure out what kind of connection you have
-if you have a good connection, rush around and destroy everyone as they have little chance of killing you unless they shoot you in the back
-if you have a bad connection and are getting insta death, then try and shoot people in the back until the host migrates again and retest your connection
thats about it
Best way to improve your gameplay is understanding how the connection, hitbox and all the stuff works. If you understand it then everything else won't be that important anymore.