I think Catman gave you a big clue -- let the waves help you rather than hinder you. Start your tack as you are going up the front of a wave. Try to time it so that you will be just past head to wind as you reach the top of the wave. Then the next oncoming wave will help to push you over onto the new tack. Easier said than done. I still haven't totally mastered that, because my boat is not only boardless, it also does not have a jib. I need more practice.

I think of it sort of like skiing moguls and learning at just what point on each hill to make your turn.