For some ABC tips/start, you should check out HoH II. It has a great section on HU play.
HU is really about adapting to your opponent, even moreso then say, 6max. amobea wrote a good post a little while back
amobea micro/macro that kindve refers to adaptation.
You should be playing a style that counters your opponent. For instance, I played some HU earlier and my opponent was very very aggressive, and semi-maniacal. He would bet with air, raise with draws/bottom pair, etc, etc
I found that if I tried out-bluffing, trying to resteal, he would push. So I tried playing super passive, c/c-ing or cold-calling 3rd pair or higher with good results.
Once he figured out what I was doing, he stopped playing so aggressively, and instead, started checking alot more/started value betting me with his better hands, etc. which destroying my passive strategy.
Its like a chess match. Play according to your opponent and you will do alright.