- Eat! It almost doesn't matter what you eat, anything helps with recovery. But since you ask, get some simple carbs in the first 15 minutes (100-300 calories). In the first hour get hydrated again, get more carbs (200-800+ calories), and get some protein (10-40+ grams). After the first hour, life as normal goes on, eat as necessary or as your cravings desire.
- Sleep! Pretty simple, you recover best sleeping. Muscles rebuild better, glycogen stores rebuild, bones rebuild, and no one really understands what happens to your brain, but we know it's good.
- Finally, move around. Preferably on the day of the event, before you sleep. Regardless of your ability to take a walk or jog after something difficult on the day, in the day and days after get out and move around.
That's about the basics of recovery. It doesn't really apply just to marathons and running, but even grieving over the death of a loved one or after a hard week at work or semester of school.