Literally! Get your feet wet. Why not start boating by taking a boat course or two to get comfortable with operating a boat and learn a few safety regulations? You received your automobile license by taking drivers education and I bet you felt more comfortable buying a car after you did. You should do the same before taking the helm.
Learning the basics of boat operation and safety is best done before your first trip to the marina or launch ramp. In fact, a number of states require powerboat operators to take a boating education course and carry a license or certificate proving successful course completion any time they're under way.
Find a course near you to get started!