There's a lot of things you can do to get better sleep. I'll list them here.
1) Exercise. Exercise is something everyone should do and most people who aren't physically active don't sleep well. Why? Because the body is meant to do physical things, if you sit or lay around all day it confuses the body and leads to bad sleep. So go out and run or lift weights!
2) Eat Better. A healthy diet usually goes hand in hand with Exercise but is a lot easier and cheaper than most may think. Instead of getting fast food meals you can get bags of beans that you can cook that will last longer and be healthier. Eggs, Chicken Breasts and Rice are other examples of good healthy foods. Also learn to love spices, they can make any boring meal taste good!
3) Meditate. Think about problems but don't over think. Meditation doesn't need to be spiritual, just set aside time during the day to think and try to solve a few problems. Limit yourself to around 30 minutes so you don't get too wrapped up in it.
These three tips should help you on your way to sleeping well!