Meditating on your psychic eyes will empower your astral vision. It is easy. Just close your eyes and "look" at the 3rd eye in the middle of your forehead. It is important to relax and not to strain your eye muscles, even though your eyes are closed. At first, there is usually just blackness, depending on how active your 3rd eye is, then possibly swirling colors and shapes. Like scrying into a mirror, the colors and shapes will give way to images when you do the meditation long enough and regularly. Remember to keep your focus soft and relaxed.
After meditating on your 3rd eye, visualize your 3rd eye brightening and shining outward like the Sun, and direct this energy to each of your psychic eyes, beginning with your 1st and 2nd psychic eyes, then back to your third eye, and up through your 4th, 5th, and 6th eye points. You can then circulate the energy up and down as a stream of brilliant light.