As someone that always likes to have everything planned out; I always fall asleep thinking about the next day.I rest my thoughts on the things i plan to do the next day, how i will do it, when and where. I just quicky do a brain analysis of all the things of the next day making sure i leave none out.
I hate to be surprised by circumstances i did not plan for and i don't like just altering my plans for the day without any tangible reason. So i really think about the next day very carefully before falling asleep.
Also, i also throw thoughts on how the day went, the things i did right and wrong. For the ones i did wrong, i try ponder on a better way i would have approached it, make the necessary ammends and create the perfect picture in my head. Everyday brings a new opportunity to become better and how can you fully face the new opportunity when you have not fully corrected the mistakes of yesterday?
Hope this helps...