I've found that most of my WILDs actually happen when I'm on my left side, and I, too, have done it before 5 hours of sleep. Mine worked like a charm, though, I guess I'm a natural. Not bragging or anything, just saying it is in fact possible. Just keep trying

I usually just think of the fact that I'm going into a dream and when the vibration waves hit me, I start thinking of what I want to dream about (people, events, places..) and I when the vibrations stop, I carefully move my hand and find I'm in the dream