The general instruction is to use a motion like pulling the sheets over your head, when lying in bed. In other words you're increasing the wind speed across the sail surface, should produce enough lift for it to clear the water. This can be done at the boom.
If you lift straight up, the clew can sink, the wind then just drives the clew deeper. If there is a tendency for this to happen, at the end of you're sheet pul trick, pull the mast back down, this should force trapped air to blow the clew out of the water.
The other method at the head of the sail works best if the sail is pointing directly into the wind, the head of the sail shouldn't be too heavy for you to lift straight up, you don't need to go very far before the wind takes over.
A few posts back, there was quite a big discussion on this topic, try a search.

Also look at your position to the wind, if you are trying to water start too far up or off the wind the wind will push the sail down. Set boom to height so it rests on tail of board, this keeps it clear of water and saves your energy. Move board so it is slightly off the wind, lift sail off board and move it around to near natural sailing angle for your position to wind as per decrepit's words of wisdom (be subtle though).

You want to be at the side of the board not the back and if you are too close to front straps you are too far upwind, you pretty much want to be as if your feet were in straps. Put back heel (gently as you can actually delam the board with repeated heel strikes)on board and feather sail to hold you there relax and get used to the sail having enough power to float you (later you can also practice moving board around like this). You shouldnt be using any effort at all really whilst like this, if you are you are trimming the sail wrong/wrong position or there is not enough wind. Now in one smooth movement throw the sail upwards (extend your arms) and kick with your front leg.

Practice trimming the sail in waterstarting type position, this can be done on land. The only time you should be using effort waterstarting in planing conditions is whilst clearing the rig from the water. Practice in flat water makes life easier too.

As you advance you will find in light winds you start a little broader and in strong winds move more to a beam reach to stop you getting thrown over the front post start.

What they said...

Here's another thread on waterstarting:
www.seabreeze.com.au/forums/topic.asp?TOPIC_ID=11440

I use the resting boom on back of board trick, it works very well, although it might wear your gear... if concerned then stick an extra bit of deck grip on the tail of your board. If your board is too short for this then another way is to lever the boom up by grabbing the rear footstrap and using your forearm to push the boom up and out of the water. I've tried this when I set the boom too high, it's not nearly as easy as resting the boom on the back of the board. When doing this, always grab the boom near the mast with your mast hand. If the wind is good then you can watch the top of the sail 'clear itself' from the waves, so now grab the boom with your clew hand and pull it towards the wind, pushing the mast hand up slightly so the sail flies clear of the water. This is decrepit's "pulling the sheets over your head" motion.

Once you're flying the sail, you'll start drifting along slowly as if you're on a beam reach. If you're too far sheeted in then you'll find it difficult for your legs to keep up with the board, if too far sheeted out you'll drop the sail on top of your head and you'll have to swim away to not drown. Now put your rear foot on the board between the footstraps, outside of foot touching the board.

You should now be able to steer the board using the position of the sail. Once you're happy with the position you're going in (slightly downwind), then pull the sail forwards, sheet in, and the sail will try to rip itself out of your hands. Think of this as a controlled catapult. You're going to harness that energy to pull you up onto the board. Once you feel yourself going up, pull the back of the board aggressively underneath your bum with your foot, then put the other foot in front of the mast. Sheet out to stop yourself flying over the front, and off you go!!!

Good luck, let us know how you get on.

interesting snippet i've read in a yankee mag... for beginner waterstarters, go to swimming pool shop, get some water "noodles" (long foam pipes) and cut a short section off and place around the end of your boom (clew end). This floats to clew end of your sail and makes getting the sail into position easier - clew doesn't sink. less energy expended more time to perfect the waterstart..

Hi Harrow

Just thought I'd add my two cents worth. I am quite small and light and have developped a different technique. I follow all the rules as decrepit said but I don't worry if the weight of the sail pushes me under while I am flying the sail. I just carry on kicking and pulling the sail over my head. This saves energy as you are not trying to keep you head above water and also seems to give me better leverage on the sail. I always thought everybody did it this way until somebody commented on what seemed like a unmanned rig waterstarting. Of course whenever possible I put the boom on the tail of the board definately the easiest method.
Happy sailing.

Thanks all.

This weekend I'm headed out with a bouyancy vest, and maybe even a pool noodle attached to the end of my boom with cable ties.

Regards,
Harrow.

Hi Harrow,

Congrats on the water starts, after a couple of sessions you'll wonder what all the fuss was about and you'll be waterstarting in preference to uphauling. But only when the wind's up, when there isn't enough wind to waterstart you'll be cursing

Now as for club secretary I'm hopeless at keeping books in order, I'll just keep whining about lack of deck grip until I finally get that first gybe in 15 knots... Gotta have SOME excuse you know!!