A skill that will be invaluable to you in a race is mindfulness. What is mindfulness? To put it simply, just noticing things around you, noticing random thoughts that pop up and letting them go without trying to block them or make them go away. The practice of mindfulness is a great way to quiet your mind when it is going in louder and louder circles of negativity. It also helps when fatigue begins to envelope you, or when some part of your anatomy starts to complain.
The process is ridiculously simple. Focus your attention on something you see. Something large and distant, something that will be in view for more than a few seconds. Then shift to the next thing. During this time, thoughts will pop up. They could be anything. What to eat for dinner. Your aching left toe. A disagreement that flared up at the office. It doesn't matter. Don’t judge them. None are good or bad. When these thoughts pop up, notice them, then let them go. Letting go means exactly that. Not repressing, not pushing away, not burying. Letting go. Picture yourself releasing a helium filled balloon, then bring your focus back to something around you.
Mindfulness is a skill, and like any skill it requires practice to master. Long training sessions are a perfect opportunity, as you will want to draw upon this skill on race day. As you acquire mastery you will undoubtedly find applications outside of training. For instance, you should find it helpful when you are having trouble sleeping. Focus your attention on the feel of the bed, the pillow, and the sounds you hear while letting go of those pesky thoughts keeping you awake. Sorry, it won’t do anything about your partner’s snoring.