Well, if it makes you feel better, I've been practicing lucid dreaming for 2 years now with no luck. I've come close but every time I notice I wake up.

I've been jotting down my dreams for a long time now, with about 100 entries. I can typically remember 2-3 dream a night.

I quite taking melatonin, on account of the fact that it makes me forget dreams and I'm extra groggy the next morning. However, it does make my dream extremely intense when I can remember them.

Anyway, I think for some people its just more difficult to get results.