Thanks to Grace Y for sharing the following link:
The Magic of Mantras
This link is a great tool for helping you find ways to build your own racing affirmations. There is no one way to do this. What works for one might not work for another. And what works for the other could work for someone else. These affirmations can change from week-to-week. You can modify them or amend them as you continue to try to improve them. You can have more than one ready to go if you know the course asks for it (one for the hill, one for the long straightaway, one for the stretch in the woods, etc).
Here is a link to the Positivity Journal for anyone who needs the reminder. Remember that this exercise works better if you make it a formal process: write it down, be consistent.