If you are too high, let off the sail power and shift your weight ever so slightly forward. Foiling is about very small movements - and even moving your hand up or down the boom a bit can make a difference. Experiment and see how changing things affects flight.
As mentioned before, NEVER let go of the boom in a crash. That makes it highly likely the foil is away from you when you go in. You may also find it helpful to remove the rear straps when you first get going. Keep at it, it keeps on getting more fun. After a while, you really become accustomed to the quiet and a planing board will sound loud to you.