Well you can modify the crosshair to a small dot.
If you get on a server with the OSP mod you can change the color to some nice day glo color like lime green or something. Not that it helps my aim but it might help you.
Failing that, just download ET which has the OSP component built into the game and go all "queer eye for the colored crosshair."
"Ohmigod! Just look at this violet purple crosshair. To Die for, it just goes so well with my Grey Axis uniform. Sieg Heil honey!"