Tips to help you wake up for Fajr (and Tahajjud!), Insha'Allah:
1. Keep Away from Ma'aasi (acts of disobedience).
2. Avoid eating too much food.
3. Drink one or two glasses of water before going to bed.
4. Perform Wudoo (ablution) before going to bed.
5. Go to bed early.
6. Make intention in your heart to get up for Fajr/Tahajjud.
7. Set your alarm.
8. Establish Fajr/Tahajjud wake up calling system with family and friends e.g. friends/family members calling, texting etc each other to help one another wake up for the prayer.
9. Say prescribed supplications (dua) before sleeping
10. Once awake, do not linger lazily in bed.
11. Go to your local masjid to pray
Also... one thing that helps that I do when I study late, or am up until the early morning, is to put my alarm clock (which is very loud) in the bathroom... thus forcing me to get up to go to the bathroom to shut it off. While you're in the bathroom, just splash yourself with water and voila! You are awake and ready for Fajr.
Okay... so you dont have to do the splashing part, but try it.. it works Inshallah.
And the above 2 advices above about staying away from sins and sleeping early is very important. It is from the Rizq (provision/bounty) of Allah that He allows you to get up for Fajr and especially Tahajjud, and when you start sinning He may deprive you from turning to Him at Fajr/Tahajjud due to your sins and having turned away from Him. May Allah swt protect us all and grant us forgiveness and abundant tawfiq. Ameen!