I was taught not to do it so never did. After seeing this thread I decided to give it a try. Did win, but I'm not sure I'd say it's "why" I won. I'm no master at strategic 1v1 by any means (I'd say I win ~50% of my games, my listed percentage is much lower, but I mean I think currently I win 50%ish of my recent games), but I think in this case the opponent was just a worse player than I am and would have lost no matter what picks I made:
http://warlight.net/MultiPlayer?GameID=3558388