1. GET OFF TO A GOOD START
Most of the amateurs I see kill their power potential with poor posture. The most common mistake is hunching over the ball with rounded shoulders. Starting like this makes it impossible to swing freely and extend your arms both going back and coming through. Your goal at setup is to create plenty of room for your arms to swing and your shoulders to turn. I do this by standing farther from the ball but keeping more of an erect posture. Notice how this combination opens up the area between my hands and legs. That's freedom to explode through impact.