The best thing you can do is to play with people that challenge you, IMO. The next-best thing is setting your rates properly (100/100/25000 if your computer / network can support it). I personally don't make my crosshairs smaller, but I know that some people do. Really though, playing with people that are better than you will force you to be a better player yourself. Aiming accurately and being able to headshot is a valuable skill, but so is patience and knowledge of maps. If you know that your enemy can't get to a location before you, you can use that to your advantage. If you hear an enemy around the corner, bank a flashbang into their face!
Kiro : us fireyes got dumb by his girl that y he is suck