I think the idea is you shouldn't eat right before going to sleep but if you plan on staying up, I doubt it'll be bad for you.

pretty sure all the don't eat before doing x activity are old wives tales. eating food will provide energy for your brain which would be helpful if you want to study.

Yeah it really helped when I just ate small salted snack a while ago.

I've found that eating light, non-greasy foods like fruits and veggies makes it easier to stay awake. But also... this should be a no-brainer, but plan not to sacrifice sleep for studying in the future. No. 1 tip.

As far as study tips go, it depends on whether you are a visual, auditory, or kinesthetic learner. If you haven't made notes, putting down key facts and answers on flash cards should help. Since these are mock tests, I recommend focussing on the aspects of the subject that you find the most difficult to understand.

I dont really know what type of learner I am and I dont have notes on this topics and generally study from the text books. I will try those flash cards ideas. Thanks :D

Also is there any good way of finding out what type of learner I am ?

STOP LOOKING AT TFTV AND STUDY BEGONE

The best way would be to get tested by a doctor who specializes in cognitive functions, like the kind that tests your IQ and also tests your ability to read, listen, and communicate. They could give you a robust idea of the best way you personally take in information. If you're looking for a quicker and easier answer that's less scientific and expensive, think about how you learned the material you've already learned. When you take an exam or are doing homework or whatever requires you to recall information, do you think about what was said, what was written on the board, what you wrote down, what you read in your notes/textbook, or something else? Or is it some combination of the above? So for example, if you think that the act of writing notes helps you remember more than listening to the instructor, you might want to take some notes as you read your textbook. Don't be afraid to mix and match. It's possible to be most efficient at, say, two methods of learning, but they are both still imperfect for you. By doubling up, you can reinforce them and allow them to cover each other's weaknesses.