like everything else, Lucid Dreaming gets easier and better with practice.

However, like everything else, you can sometimes have off days. If you find that you're getting better and suddenly go through a dry spell or even simply have less vivid LDs, don't freak out. That's the part that always frustrated me. Whenever I thought I was getting good at it, I'd start losing my streak and get really frustrated. Patience is probably one of the most important things in lucid dreaming.