1. Don't worry about sleep. Try to go to bed early enough to get enough sleep, but if the sleep won't come, don't get overly worried about it.
2. Every morning wake up at the same time regardless of wether you have to or not or wether you have slept enough or not. Try to get out of bed as soon as possible.
3. Do a lot of stuff through the day. Especially physical activity, such as working out, taking walks outside etc. Try to get a lot of sunlight too.
4. Try to relax for the night and make sure there are as few disturbances to your sleep as possible.