When Source first came out, I was shocked that you can play with your xhair scale, thought it was awesome, so I made it tiny (9999) at first, and notice an improvement as well, but when I changed it to a larger one, and switched my style and thinking a bit, I notice a dramatic increase in headshots + kills in general.
Do you want to get rid of the crosshair movement? If you do, type "cl_dynamiccrosshair 0" to remove it.
Well, I suggest once you've peaked at your small crosshair scale, try switching it back up to a big one, just to see.
Jus' trying to help! 90% of the people I recommend this to admit that they are better that way.
Also, how long have you been playing?