Since I've gotten into Lucid Dreaming I've remembered about 2-4 dreams each and every night. It's been amazing, going from thinking I don't dream to this.
But yeah, try setting your alarm clock 6 hours after you go to bed, since you should be in a REM state then. If that method doesn't work, just tell yourself as you go to bed "I will dream, and I will remember my dreams" over and over, and try to make it the last thought you have before you drift off.
As long as you take this seriously, and keep it of high importance, your mind should want to remember it, making it that much easier.

Hope I helped. ^_^'''