These are the things that worked for me when I broke the record for highest amount of credits taken in a semester at my university:
Highly recommend caffeine pills. The benefits of caffeine without sugar, $$$, yellow teeth, trips to the bathroom, etc.
Take short naps throughout the day, or find out what amount of sleep works the best for you. Oftentimes you can feel refreshed after sleeping just 90 min, but it depends on your sleep cycle. There are some mobile apps that can help you figure out what amount of sleep you need. DO NOT oversleep, you will feel sluggish afterwards.. so it is very important to find out your particular cycle...
Sometimes an all-nighter is required - just make sure you take good care of your body after it and don't do more than 2 all-nighters in a row. If you are planning to do an all-nighter, don't use too much sugar or caffeine to stay up because that will make you crash sooner than you had probably hoped.
Plan out your goals for each day for the next two-three weeks (depending on what you have going on) so that you are not overwhelmed with too many things in one day. If you set a goal for yourself to finish so-and-so thing then that will help with procrastination AND stress.
Change your environment every once in awhile too! Maybe even work outside! And don't forget to take breaks that have nothing to do with homework or studying.
Again these are just tips that have worked for me. Every person's body is different and I am one of those people that can survive on a smaller amount of sleep. The key is moderation. Slow and steady wins the race, not 5 all-nighters in a row.