I've been doing some practice of this earlier today. My sticking point is worrying about my calf being hit by the pedal as it whizzes around, which of course has never actually happened. I straddle the bike in front of the saddle, with my dominant pedal at about 2 or 3 o'clock, push down hard and hope. I'm a bit wobbly when setting off but hopefully that will sort itself out with time. It's a great thing to practise in a carpark or on a cul de sac with hardly any traffic. My instructor gave me 10minutes work on it at the end of a lesson when it became clear I was struggling to set off on a short steep uphill gradient. I agree with gradually raising the saddle too, my riding is so much more comfortable and I'm sure I can go a little higher still once I'm comfortable with starting and stopping unseated.