Try to read about LD'ing every night before sleeping (or at least think about it) as well as right before you take a nap. Also, KEEP A DREAM JOURNAL! I can't stress that last one enough. I thought that my recall was good enough, since I usually remember my dreams from the night before quite clearly, but after starting one I could remember three to four dreams every night. And the more dreams you remember, the better you know what to look for to tell if you're dreaming or not.