Your body is a machine that tries to establish a routines to keep all of your body functions working harmoniously. To help your body develop a healthy sleep cycle you must have the discipline to go to sleep when your are suppose to, and most importantly, get up when you are suppose to.
I had a horrible sleep cycle all of my life, but it was due to other genetic factors. My training was ok, and my grades were descent, but it wasn't until I started going to bed at 10:30pm or before and getting up at 7:00am that my gains in the gym, and my grades in school took off.
Sleepign is probably one of the toughest factors in your life to control, because life gets in the way. Someday you want to go out with your friends and stay out all night, but you have to keep in mind that this is hurting your athletic performance.
So, now you have to make a decision. Do you want to be a top notch athlete, or do you want to stay up all night goofing off?