I have a few questions on heads up strategy. I usually play for like $2 or $5 at the moment, and seem to win around 50% although lose money due to the house cut. I am finding it really hard to do certain things - firstly I never raise a shjit hand, i would always call or fold really....how often should I mix things up?

Can anyone suggest any other tips i could use specifically for heads up?

thanks
Andy