It's awesome to see so many of the SourceOP'ers getting interested in comp play.

I'll try to answer any questions you might have but are unsure of who/where to ask otherwise. The wiki guide and the Steam sticky post are awesome for getting the ball rolling, but there's much more after that.

My initial words of advice are these: There are insane players of the likes most SourceOP regulars have not seen and entire teams of them. Pace yourself and don't get discouraged if you get rolled by them, they too started out where you are right now. Comp TF2 is like a brand new game, it can be tremendously fun as long as you keep perspective.