First of all physically speaking, research shows that cool temperatures help with falling asleep. 2 pieces of advice about this may help. First try cooling off your room, turn on the air conditioner if you must or open the window. If you get your room to 15-19 degrees Celsius which is 59-66.2 Fahrenheit you will get to what researcher say is the temperature that helps you fall asleep. Cold helps the body produce melatonin which helps bring on sleep. That together with darkening the room should work.
If cooling off the room doesn’t help try cooling yourself off. Wash your face with cold (even ice) water for a half minute. This helps calm pressures and also stimulates the “diving reflex” which mammals and humans both have which slow the heart rate and lowers blood pressure. Washing your face will help bring on drowsiness.
Second of all psychologically speaking, quite often people can’t fall asleep due to pressure to fall asleep. People are so under pressure to fall asleep and get as many hours as they can sleeping that the pressure prevents them from falling asleep. So the first thing you should do is hide your watch and try to stop checking what time it is every few minutes and how many hours you have left to sleep and just calm down.
Another method can be using reverse psychology; instead of trying to go to sleep or even relaxing and calming down which doesn’t always work, try staying up! A study from the University of Glasgow Scotland found a way to fall asleep quickly. Try to lie down and force your eyes to stay open until they start closing on their own. For some reason trying to stay awake makes drowsiness come quickly and with it sweet restful sleep. Try it!