The recommandation are four keywords: Preparation, hydration, sleep and nutrition.
Facing a sporting event without proper preparation is risky.
A good technique is to reproduce the conditions of the competition, and to particularly heal the recovery through stretching. Work on stress through breathing exercises, relativizing and repeating that you are well prepared.
Hydration, sleep and nutrition will be your three key words until the competition. Get enough sleep to get fit: Drink water before, during and after exercise. Finally, pay close attention to what you put in your plate: balanced foods, high in carbohydrates (the day before the competition) and in slow sugars like cereals, pasta and rice.