Having a consistent sleep schedule can be pretty vital. Do you sometimes sleep for 5 hours a night, only to get 10 hours of sleep the next night (or something along those lines)? Try to get the same amount of sleep every night. Going to sleep early can also help. Sometimes I'll go to sleep past midnight and no matter how long I sleep, my recall will be awful. But if I go to bed sooner than that, my recall will be much better, even if I don't sleep in as much. But as Empedocles said, getting about 7-8 hours of sleep will definitely facilitate the process.

Also, do you wake up after about 4-5 hours of sleep to write in your dream journal? (Or whenever your REM cycles end, if you've managed to figure that out.) When you do this, make sure to go over all of your dreams in your mind before you move around too much. Only sit up and turn on the light to write in your dream journal when you've remembered as much of your dreams as you think you can possibly remember and you've gone through them over and over in your mind. Using an audio voice recorder to record your dreams can be pretty handy in this process, as you won't have to turn on the light and wake your brain up if you've set the recorder down on a bedside table and know where it is.