Something else that helps me, if you're wearing a waist harness is to twist your body so that it faces forwards a bit. Your harness will twist slightly on your body, allowing you to lean a bit further forwards.
This upwinder and downwinder was done on a wave board with a small fin, which normally you wouldn't think would smoke upwind. 5.2m sail, 23cm wave fin..
Apart from that WindXTC has all the other tips that help.