Set time aside regularly for study and tell everyone, so they won't disturb you. Study regularly for short periods. Do whatever exercise you usually do and eat and drink well. Drink water not coffee while studying. Be aware of when, where, and how you study well.
Some people work best in a quiet library, others study best first thing in the morning.
Find the best time, place and method for you. Prepare for the marathon. Before the exam do a few one hour or two hour study sessions for stamina practice. Also don't rely on coffee or music that won't be available during the exam. Know the exam format.