I’ve been drinking canned soda all day and yeah, I’m pretty wired. I’m worried this will have effect on me dreams. Does anyone know a way of calming yourself down? Thanks in advance! 
Notice the effects (specifically, ie heart beat and breathing, any sort of concentration problems, etc) of caffeine or whatever it is you are drinking. Sit down or lie down somewhere and focus on these things, actively attempting to change them. The same way you can control blinking or breathing, you can control heart beat and other things if you focus well enough.
how do you focus to change your heart rate and other things while asleep?
Sometimes on nights when I have trouble falling asleep I find that this mp3 I have really helps calming me down. I found it on KazAa and it has helped me greatly; the filename is : Self Help - Hypnosis and Relaxation - Deep Sleep Meditation. The file is a total of 28 minutes 6 seconds long, which I usually listen to once before getting relaxed enough to fall asleep. At first, the woman’s voice on the tape doesn’t seem very relaxing, but then she really gets into it and you start to doze off 
If that doesn’t work, try different forms of meditation. totse.com and erowid.org are piled with information on various articles about lucid dreaming (and various psychadellics hehe).