Wipeouts are inevitable and the first priority is always to avoid hurting yourself or others. Raise arm to protect head if sail is falling on you. Also, try to reduce the chance of equipment damage. If possible, avoid letting the mast & boom fall directly onto the board; this is the most common cause of board damage. Avoid falling onto the sail and possibly damaging it with a knee or arm - if you start to fall toward it (especially when first learning the harness), don't let go of the boom until the sail is in the water, then roll off to one side. Getting familiar with the experience and developing muscle memory is the key to improving skill and confidence.