yep ditto laurie's advice, the tip i offer concerns gybing- firstly let me state i know i am one of the worst offenders

, so i am no expert, how ever from watching a lot of sailors i have noticed the most common problem in my opinion is the failure to plain-thru or even carry any speed thru the gybe. this problem is not isolated to just new comers but to lots of seasoned/experienced sailors as well.
the prime cause of this (imo) is due to the sailor getting caught too far back on the board especially after the board has passed dead down wind.this tends to sink the tail thus creating drag and slowing the board almost to a stop which then in turn, allows the 'pressure' in the sail to re establish thus adding to the drama, usually resulting in a swim for the less experienced.
i think the key is to keep your weight forward thru the turn. try and time when you let the sail go and grab it on the new tack to shift your 'new' front foot, all the way forward at the same time, even stick it as far as the mast base.then move back into the straps when starting to plain again. this should keep the board flat thru the turn and hopefully in turn keep the speed up.as i said before i am no expert this is just my observation, in summary the easiest/quickest way to improve is to get some lessons from the guys/gals who know!! good luck.

snides8