Looking for a few pointers!
From a positional point of view do you simply fly the sail as you would normally and then move the board until it is pointing in the correct(opposite) direction? I have found that it feels as though it might need topoint more off the wind than normal so that you are getting on to the back of the board more.
Compared to a normal start do you still offer the sail with the mast hand and put the back foot on first? and do you apply downward pressue with the mast or clew hand?
Any other advise would be appreciated... apart from the general usefulness of the move for waterstarting I am trying to increase the amount of rig flip practise for gybing, especially in light winds.
keep your front foot up close to or even just forward of the mast base when w/s clew first 
everything else with the waterstart is pretty much the same for me
Clew first is a good one to learn anyway, just incase you find yourself in the water in a shore break and need to get going in a hurry, I am a gumby and I can do a clew first w/s.
Learn it, ya never know
GT
When you waterstart, you'll probably need to keep the board at 90 degrees to the wind like usual to get max force to lift you out. But once you're going, it's harder to sail clew first on a beam reach, so head more downwind. Because the centre of effort of the sail will be further forward, you need your front foot right up in front of the mast foot and your front hand needs to be further forward than usual on the boom to counteract the extra pressure on your front hand.
everything else with the waterstart is pretty much the same for me
With fin first water starts, as 555 says, the trickiest thing is keeping the board lined up. What happens is that the slightest bit of mastfoot pressure pushes the nose (the bit you climb up on) away from you, so you have to line up the board more downwind and get a foot up very early to stop it moving away.
Once you're up you have to sail fin first so you should practice that a bit, that and fin first to orthodox transitions.
Hmmm... it just occurred to me that once you're going fin first, you should be able to transition to orthodox clew first in the opposite direction just by stepping forward. Must try it.
Another option for getting a board back up the right way with out dropping the rig is to get in the water start position, sheet in to let the rig get a bit more vertical, then pull the boom away from the board (instead of trying to get it as high as possible) while simultaneously giving the mastfoot a shove away from you, and up with your foot. That should flick the board over..
I remembered this last night after horribly mangling a jibe attempt just when I needed to get it right!
