All it is is a lot of practice and as soon as you know your front tyre has cleared the front of the wall you need to throw your weight forward and aim for the corner. You cant really think about it when you are doing it as it's such a quick movement, but if you start with smaller stuff, get the technique spot on the height and consistency will come in time. A lot of it is psychological, not committing and thinking 'what if i come up short with the front wheel and go over the bars' but once you get a feel for it the move kind of becomes muscle memory.