everyones gonna say this.. but just practice. i know what it feels like when just starting off learning them, i thought i'd never get my balance and keep up-right, but in 2 weeks time i started to improve and now 2 months later i can hang 5 whole netball courts.
the best advice is:
1. put alot of pressure on your arms and push it straight down into your bars ( keep your arms pretty much dead straight once you got the balance point).
2.try and lean forward almost as much as you can without flippin over your bars. because this is the balance spot, (DONT BE SCARED TO FALL FORWARDS! think that when trying them, it makes them around 3 times faster to learn).
3.have the foot that wves around in the air pointing straight down.
4. and have your other foot with a little over half your toes on the very starting bit of the headtube, and the rest on the deck. and make sure that your putting all of your pressure on your bars and front part of your foot. i hope this helped, and that you can understand it all properly.