Whoever suggesting OP to sleep after midnight and before dawn, should themselves worry about their sleeping habits.
Anyway, [MENTION=287925]kml420[/MENTION]: Some suggestions:
1. Don't sleep in day, no matter how sleepy you are. It will be difficult at first, but slowly your body should adapt it.
2. Start watching a series. Any series: HIMYM, Lost, Game of Thrones, Heroes, Breaking Bad, Prison break... any. Watch one episode every night before you want to sleep. Don't do marathons. At max two episodes if you are curious after any cliffhanger. Try to sleep after that, thinking about what would happen next!
Do just these two things. Works for me everytime.
Disclaimer: This might improve your sleeping habit, but could make you addictive to such show! So its your choice.
Do some exercise. That always does it for me.
Or you can listen to music while you are in bed. Make the music player or your phone stop playing music at a specific time using the sleep option on it because you don't wanna blare music even after you fall asleep.
If possible, remove all your digital devices from your bedroom (assuming you're not staying in hostel).
If you can't resist, install an app in your PC to sleep after the stipulated hours.
If you still can't resist the digital life, make a self-rule like 'no devices after 12 PM'. (something like that).
Some of these ideas could actually be detrimental to your sleep!
Reading - I used to go sleepless for 2 - 3 days until I finish the novel in hand.
Series - This keeps me awake till morning nowadays.
Exercise - Not guaranteed. Although sometimes it makes me sleepy some other time it leads to chasing away what little sleepiness was there.
What works for me:
Studying invariably induces sleep though.
Another suggestion from my side is to try self-motivational audio books. They will always put me to sleep.
Count the number of sheep in your imaginary field.
Mentally try to calculate the value of 'pi' to the most accuracy.
Try to relax your limbs and muscles one by one until you feel no control on your body.