Some people actually don't see anything behind their eyes when they close them and focus on the darkness - but you can train this!

Instead of sitting and waiting for HI, try and make your own! Start really simple, try and look into the darkness of your eyelids and make something, a red triangle, a green circle, etc. If you're looking for colours, blobs, etc, then trying to make your own will help a lot more In terms of using it to WILD, visualising full dream scenes will benefit you a lot more, and will still help exercise the dreaming part of your brain