Here's a copy-paste from my DILD guide. It really helps me to remember dreams if I'm going through a dry spell.

When you wake, try just relaxing in bed with your eyes closed. Focus and think of key words, seeing if they resonate with something you dreamed about. Staying relaxed helps keep your brain in "sleep mode" for a few moments so you may be able to recall dreams easier. Or, you can always go on Dreamviews and read other people's dreams to see if they remind you of one that you had.
You'd be surprised how many times I've remembered dreams when I logged onto DV!