How to stay awake when you need to?

caffeine tablets or energy drinks

Sugar, food/carbohydrates, trying to get enough sleep. I have been extremely tired lately at work in the evening though so perhaps I am not beat to give advice lol

Caffeine will keep you awake but your heartbeat will accelerate too. Best to sleep well during the night so you can focus more during the day.

Adjust your sleep pattern. Make sure you're getting enough sleep at night. Take a break. If you feel yourself nodding off, get up, take a walk. Get the blood flowing in your body. If all else fails, take a power nap. 45 mins to an hour max.

Once you are addicted to coffee your intake gets higher because 3 cups of coffee can no longer satisfy yourself and so you will have another to make it four. The time interval now to being asleep and awake gets shorter. When you feel asleep it is your bodyclock that dictates and so you need to follow it. Take time to sleep for at least 10 minutes set your timer. You need to rest or your study will go to waste.