When you are getting enough REM sleep, an active way of remembering your dreams is by maintaining a dream journal. You will only remember dreams when you wake up directly from the dream. If you go straight into a deeper sleep without waking up then your dream will be lost forever. So set your alarm clock to go off after you had 4 ½ hours of sleep. With some luck, this will awaken you during your REM sleep and you can recall your dreams.
Log into http://explainthisdream.com when the alarm goes off and enter all the details you can remember. If you do not recall anything, then maybe you were not dreaming yet, so maybe 4 1/2 hours is not long enough for you and you should increase the time on the next attempt. Keep increasing by 1/2 an hour until you find the right cycle where you wake up with a memory of your dream.
When you are describing your dream, write in the present tense and include all the unusual circumstances, scenes, plots, symbols, emotions, themes etc.
You have to set your alarm to go off in 90 minutes (this may vary from individual to individual so experiment with different durations) and go back to sleep. Keep repeating this trick every xx minutes till you get up for the day. By morning, you should have written down 4-5 detailed dreams. This is a great way of boosting your dream recall.