@DR13: It's no guarantee, but Serena is not far off; being aware without the knack or a lot of practice is tough, and often wakes you right up.
One old trick is to set your alarm for roughly 5 hours after you go to sleep. Wake up, but don't do anything, and rapidly try to go back to sleep while focusing on your awareness. sleep cycles come more rapidly, and last for less time the longer you've been sleeping, so you can jump back into REM pretty quickly, maintaining awareness all the while.
One thing... it can be disturbing, because on the way you WILL experience hypnogogic hallucination, but then it can be fun too. If you find yourself waking in the dream, try changing the scenary or just spinning about in a circle. I haven't the faintest as to why, but it often works.