The most important thing is to ground yourself within the dream immediately after you become lucid. Remain as calm as you can, reminding yourself that you're dreaming over and over again, and touch things. That sounds stupid, but it really helps to see what things in the dream feel like; it'll help you forget about your physical body and make your mind work to create more dream sensations.

Like moongrass said, "dream spinning" helps too, but don't spin too fast, just enough so that you can see everything around you. Going too fast will destabilize the dream.