Actually, if I remember correctly, it is when you wake up while you are still in REM that you remember dreams most. So tell yourself you will wake up in the middle of a dream or something of the sort.

But to be honest, I just use an alarm clock. Easiest way.

For me, the question is not how to wake up, it is how to stay awake.
I tend to have lost my motivation when I wake up, because I am so tired, so i end up going back to sleep again.

Of course the only way to solve that is will power.

But I am talking about WBTB, and you are just talking about recall. So this problem doesn't matter quite as much as you just need to write down your dreams and go back to sleep.