Gripping the pedals...a scratchy technique
1° Pull the smoothest pedal hop sideways to reach your bad pedal on top of the grippy edge, your driving pedal is opposite the obstacle.
2° Hook the pedal (and when possible also the front wheel) on that edge, and try to hang to it by shifting your weight over it.
3° Once you've reached some balance, recover a standing position on the pedal that hangs onto the obstacle, good foot up.
4° Balancing on one leg, flex to prepare your extension for stepping the rear wheel up.
5° Full extension in a one-legged static hop, pulling up the bike to its final position.
6° Either land to back wheel if the edge is narrow, or secure both wheels onto the obstacle.
See this move in a video, and the second part (hop to backwheel)
Hooking the right pedal, over a gap
How do you get there?
If you have room to land the front wheel across the obstacle when gripping the pedal, then you can use that extra support and roll onto the front wheel (leaning forward) to lift the rear wheel, instead of relying on a one-legged static hop. Ensure a comfortable grip with both wheels. To make it useful, you must be able to stay in balance on one foot while the entire bike is hanging over the wall. It is not that easy, as the bike tends to drag you off-balance as you hang desperately to that suffering pedal. It is especially awkward if you end up completely flexed on the bike, at the maximum height of your pedal-hop pulling capability. From there, try to slowly recover a comfortable position on your standing leg, before you launch a one-legged static hop to bring both wheels on top of everything. Alternatively, take a break and scratch your head for the next move. Try on both sides, as you may have a favourite side that's not always obvious.