Self-affirmation usually works pretty well for me... When I really want to do it, I have a whole check list I go through. A typical list is something like:

• I will have a clear and vivid dream
• I will become lucid
• I will have a lucid dream
• Upon becoming lucid, I will remain calm and in control
• I will be able to easily control myself and freely move about
• I will be in complete control
• I will be able to prolong the dream by _insert_prefered_method_here_
• I will remember to _insert_something_you_want_to_remember_to_do_here_
• When I wake up I will be able to easily remember my dream

And then repeat it a couple times. I don't do this every night, but when I do it has a pretty decent chance of working and when it does I almost always remember the things I told myself I would remember. I find it works best while lying in bed right before going to sleep.