Some odd advice in here
You need:
1. enough power to be able to water start easy (get up over and on the board)
2. enough wind to be able to just sheet in and power up comfortably
3. a small enough kite to be able sheet out and dump the power and turn snappily
4. a kite you're comfortable enough with that you don't think about it when flying it one-handed
In the beginning, you'll probably ride the same size kite as lawn mowing with your TT, until you can foil consistently--then you'll drop right down in size.
Big kite, light wind = sucks. Small kite, high wind = sucks.
Find your own balance of wind and kite size; for me, it was a 10m kite in about 15 knots.
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Straps . . . assume the designers and builders know what they're doing, and the straps are situated for good balance. Moving your foot ahead of the rear strap is not a cure, it's treating a symptom of bad stance. Get it right from day one.
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Stance. Don't push or lift your feet--lunge.
Ride the board flat. Stand bolt upright, flex both your knees and side lunge onto the front foot, like this:
...but without looking like you got caught playing with your balls.
Keep your torso upright and straight, bend your front knee more than your rear, and move your weight forwards.
Why do it this way? Watch yourself in a mirror. You move your CoG and almost all your weight over the front foot.
Do it again, now push or lift a foot, and watch. Your CoG almost doesn't move and you actually transfer weight on the rear foot. Good luck with that! You can sidestep the problem by moving your feet together (rear foot forward) but that's a crutch.
Lunging is more stable. Slower to react to changes, sure, but stability is the key at this stage.
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Back to straps. You *can* learn with front and rear straps, but open them up to be as wide and lose as possible. As you water start, you might feel the need to jam your feet as far forwards as you can but if you have good stance, soon you won't have to.
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Speed is your friend. Like riding a bike or learning to ski.
If your stance is right! Ride with the board flat on the surface and go faster until it starts to push against your feet. There you are, you're foiling. No really! And you're not porpoising!
Why? Because if you try to ride slowly, the foil will be near stalling speed and it will be constantly trying to pitch up as it stalls. Trying to fight that when you're learning sucks.
Go faster. Probably just a little faster than you feel comfortable with. And always have a plan for bailing out