The above post is very true, especially with surgically related specialties. For example, if you're an OB-GYN doc (especially if you work at a busy hospital) you can expect to be sued about once or twice every decade of your career.
Keep in mind most medical lawsuits are filed over poor outcome, not necessarily poor physician practice. The majority are tossed and don't make it through court. But if you are truly worried about it, work on your bedside manner. It's been shown that patients are far less likely to sue a doc they have a good rapport with.