I am still a student and I am about to join college. Here are some hacks I have found till now( mainly experiences of JEE preparation)-

• Don't ever multitask while studying, it really disturbs intake capacity much more than you think.
• If you are feeling sleepy during late night studies, you can listen to loud music. I used to listen to Linkin Park. It really helps to study for longer hours. However I personally feel that this should be done only when you are really sleepy. Otherwise it reduces concentration. And don't do it for longer durations as it may damage your ears
• You should make short notes. They really help in last time revision before exams. Just formulae and important tricks, nothing fancy.
• Group studies should be avoided as mostly I used to spend most of the time chatting with friends. It can be done for discussing doubts.
• While taking breaks try to avoid activities which tire your eyes or body in general,i.e., avoid mobiles and heavy sports in the break. It will tire you even more. Better to do all this after your study session is completely over.
• If you really think you are unable to maintain concentration due to your phone, you may use apps like Study Helper which locks your phone for a fixed duration.
• You can maintain a diary where you can write the amount of progress you have made till now and can set targets for next day, week, etc.