3. DO NOT use "wellknown" speed trimtips always/every session (mastfoot in back, high boom position, long harness lines). Make sure you play with your equipment, you may do better with a slightly shorter line on a different sail for example.
4. DO NOT use one the same exact setup or setting in varying conditions. It pays to tune your kit, you will learn far more quickly how to get the best out of your kit this way. One small tweak could give you an extra knot in one condition and lose you a knot in another.
5. DO NOT sand your windsurf board for that last .1mm perfection, its a waste of money/time and most likely the board will break down much easier. Since I use starboard (2010) haven't used a sandpaper and best decision ever (both financial and from time point of view) (late edit from Redsurfbus - sorry Erik I won't do that again then ;-)
6. DO NOT EVER sell all your equipment and start over all new, I mean what are you doing windsurfing or puzzling? Think about what we have said in point 2, you spent all that time learning how to use your kit.
7. DO NOT buy and use real speed equipment on open water or onshore winds, do you really think you will go faster? Your speed board is designed for flat water which can only really be found with offshore winds close to the shore or at least with something that breaks the surface of the water to stop the chop.
8. DO NOT think 2011 is faster compared to 2007, maybe a 2007 will break down easier at the first catapult/ big impact on wave/ gust, or maybe that special team finish on the 2011 kit is much more fragile than your trusted 2007 tatty old board.
9. DO NOT EVER go on the water on a offshore spot without a decent plan B (when your windsurf kit or your body fails sailing upwind)