Getting to Sleep Quickly

This is something that I struggled with when I was sleeping normally (or what most of the world calls normally anyway). I would lay down in bed at night and let my mind wander. I would think about the current day, what tasks I accomplished, which ones I still needed to do, what I could have done differently. I think about the next day, what I've got planned, what homework I should have done instead of playing video games, whether or not I need to attend class in the morning. I then also think about random things, what should I get my mom for Mother's Day in 3 weeks? What's something special I can plan for my anniversary in 8 months? What would it be like if I could control fire, and had a pet velociraptor? What would life be like if I were a midget that could breathe underwater? You know, weird stuff...