Nothing you learn on the night of June 6 is going to appear on the paper of June 7. Cramming that night costs you sleep and adds almost nothing to what you know.
Have your bag packed by 8 p.m.: admission ticket, ID card, pencils, pens, ruler, compasses, eraser, water bottle. Lay out tomorrow's clothes.
Eat a light dinner of something you eat all the time. No coffee after 6 p.m.
Spend thirty minutes reading for pleasure. Not a textbook, not a mock paper — a novel, a comic, anything that is not the exam.
Be in bed by 10:30 p.m. If sleep does not come, do not panic: lying quietly in the dark gives you most of what sleep would. Leave the phone alone.
Set two alarms. Trust your preparation. Turn off the light.