Taking gaming to the next level?

Hi so i play call of duty a lot mainly mw2 but now black ops and now I'm really good and i would like to to take it to the next level. I was wondering what suggestions you have, i was thinking about joining. Big gaming group like mlg or something, but I think i want to start at s lower level and work my way up. Also any strategies on maps would be nice because I have a lot of skill but I usually just run around like a dumb *** preventing me from getting a bunch of kills :P thanks!