Gary, try the beach technique first. It doesn't damage you or the equipment. It's a good starting point.
You really don't need to close your eyes, you don't have to be going fast, you don't have to jump high. Just get the feel for it at a comfortable speed and height etc. You begin to gain confidence fairly quickly after you try some, regardless of whether your feet stay in the straps or not. The scariest part of the whole thing is a side on catapult which is a result of pointing too far into the wind when attempting them. If you jump off baby chop while heading a little down wind, I can virtually guarantee you wont slap side on.
Most important - don't let go of the boom no matter how bad your attempt is. (slow or fast, low or high) Practicing step 1 and 2 will get you used to hanging on right through.

H