9) Relax – this is sometimes the hardest thing to do. You have registered for the event, picked up your swag pack, walked the expo, bought the souvenirs, ate your pre-race supper.
Now, relax and trust in your training. Trust in yourself. It is second nature to double guess yourself (and your training), the last night, or the last week, before your big race. You know that you did the best you could in preparation for this event. The running group, the stories, the comradery, the presentations, the question/answer periods, it all comes together. Watch a favorite movie, eat a little popcorn, drink some water. Laugh a lot. Get to bed a little earlier than usual and try to get some sleep (I find it is the quality of the sleep, two nights before the race is more important than the sleep of the night before your race).
Taken from: https://www.all-about-marathon-training.com
Have a great race!!