Dropping off a wall frontally: balancing on the rear wheel to prepare the jump.

For this technique, you should know first how to hop on the back wheel, staying in balance on a the edge of a kerb, and also how to pedal kick. Or you won't be able to decide when you are ready.

Dropping Off From a Pedal Kick
Balancing on the back wheel, adjust your tyre on the edge of the wall/kerb with a few hops.
1° Like for the pedal kick, lower the front wheel nearly to the horizontal before you pedal off the edge.	2° In the air, extend your feet and arms and let the rear wheel drop so that it touches ground first.	3° Rear brakes "on", damp the impact progressively by leaning your body backward. See the physics of landing.
When the front wheel touches, most of the impact should already be absorbed by your legs and arms. The front wheel shouldn't bang on the ground (a wrist breaker).
See the move in an animated gif

Landing smooth? In the air stabilise the bike aligned with your body, otherwise you're likely to be ejected sideways, on impact with the ground. Let the back wheel hit the ground first, with the rear brakes "on" to gain extra damping power as for the sideways jump. Also, using the rear brakes will prevent you from slamming the ground with your back (not so healthy).Use the spring of your legs to absorb most of the impact, then lowering naturally the font wheel to the ground by extending the arms. Here again, fat low pressure tyres are more comfortable.

Stabilise your bike

The next step is to drop off from a natural wheeling. If you have enough space for two pedal strokes, start on the goofy pedal lifting the front wheel, and the next pedal stroke (with the good pedal) should send you off the wall. Also you can try out some other stylish techniques like the front turn or the 180° twist.