hi, welcome to the board!
I find with HI it's best not to concentrate too hard at first, and then i find an image i work with, and i try and build a story around it in my head. I've come close to acheiving wild a few times in this way.
Also, try not to do it as soon as you've got into bed, your natural instinct is to fall asleep!
I find it best to try it in an afternoon nap..i've got closest then, but haven't yet been successful.