The sleeping is pretty important. 5-6 hours of sleep drops you right into the area of sleep where REM is the most frequent. Some people can WILD from a fully awake state, but not most.

So, with the vibrations and all, have you entered sleep paralysis yet, and have you begun to see hypnotic imagery? If you've entered sleep paralysis, and you're seeing HI, you're pretty much there. Reaching the HI stage is dificult, and the only way there is patience, self control, and maybe a slight amount of sleep-onset insomnia. Heh. Anyway, once you're there, focus on the HI without forcing yourself to. Just kind of take the back seat, and let things flow, but make sure your'e conscious of what you're observing. You can't actually WILD without drifting to sleep, but you have to make sure that you're not slipping into unconsciousness at the same time. It's not easy, and it's the reason why not many people are good at WILD, but it's worth it.

Another random tip is to try drinking a can of Coke or Pepsi, the caffeine helps some people to stay awake long enough to maintain consciousness. Mountain Dew, coffee and such usually are too much caffeine, but it varies on the individual.