Heads up problems

Any tips for a beginner.

Problem I have is that I play ring games better than tournaments but I like tournaments. I've narrowed the problem down to heads-up play. I typically get into the top three of small STT's (around the $5 buy in) but I always seem to loose the heads up.

OK I win a few but those are usually the ones where the stacks are even and we both go all in with good hands. If the play lasts any amount of time I end up loosing.

I'm sure that I'm not aggressive enough but I find it very hard to bet holding nothing but 93 off

Help!!!!!