Good Heads up threads for beginners?

Ive found that a bad heads-up player is very easy to beat and at some sites, I stand a good chance of building my bankroll through HU sit and Go's. I'd like to become as good as I can be if I'm going to play this form of the game; What are some good threads to sharpen my Heads-Up tournament game? Also, what are the best sites to find the softest HU competition at the $10 and $20 SnG levels?