Also, I recommend you put your focus on the back of your eyelids. That black space, when given adequate, stable attention will slowly begin to come alive with colors, patterns, scenes and all manner of things. You can get a "temperature" on how deep your trance is, and how ready your attention by simply keeping focus there and watching the scenery unfold. Once the imagery starts taking shape you want to passively observe...don't roll your eyes into position to track images as they come and go or you wind up sending too many signals to your brain. Eventually, an image will settle smack down in front, open, and many can enter the astral by doing a point shift into the very scene.