Meditation before bed and going to bed early after taking some melatonin tends to give me more vivid dreams. The wake-back-to-bed technique often works to give me short lucid dreams. I think the trick is that when you wake yourself up in the early morning, you become awake and alert after the early-night deep sleep phase that would otherwise leave you groggy and completely out of it. Then when you go back to sleep you go to lighter REM sleep because your sleep cycle is still running, but are more likely to be alert and recognize it's a dream.