A: Many things. Your lawyer can prepare for the preliminary hearing by spending time with you, learning about you, learning about what happened (or didn't happen) that resulted in your charges, and begin to develop defenses and outline a strategy for success. Your lawyer can learn about the circumstances surrounding the allegations, conduct his own investigation (perhaps even work with a private investigator), interview witnesses, inspect the scene, take photographs, identify legal issues, conduct legal research (and do various other things which depend on the unique circumstances of your case). All of this preparation is made in an effort to identify and develop possible defenses to the charges. It's all part of forming a plan for how to defeat all or some of the allegations.