Take it easy the day before.Make sure you get plenty of rest the night before, aiming for eight hours of sleep. The day before or two days before your long run should be a complete rest day. If you do train the day before, it should be an easy run or workout.
More: Are Rest Days Necessary for Runners?
Hydrate and eat properly leading up to the run.The two days before your long run (and your marathon) should be high-carb days. You should make sure that you increase the percentage of carbs in your diet, not the overall calories. Carbo-loading does not mean that you should eat three plates of pasta for dinner! Aim for at least 65% of calories from carbs during those days. You can still have some protein but, for example, instead of having chicken with rice, have rice with chicken. Drink plenty of water and nonalcoholic fluids. Not only does alcohol dehydrate you, but it can also prevent you from getting a good night's sleep.
More: What Should I Eat and Drink Before Long Runs?
Eat and drink something before you start.You should eat a small meal about 1 1/2 to 2 hours before you start running. Choose something high in carbohydrates and lower in fat, fiber, and protein. Some examples of good pre-workout fuel include: a bagel with peanut butter; a banana and an energy bar; or a bowl of cold cereal with a cup of milk. Stay away from rich, very fatty, or high-fiber foods, as they may cause gastrointestinal distress .
More: Best and Worst Pre-Run Foods
Do your long runs at the same time as your marathon.Make sure you do some of your long runs at the same time of day the actual marathon will be held to familiarize yourself with running at that time. You'll also develop a pre-race routine that you'll be able to do on marathon day.
Don't overdo the mileage.For recreational marathoners, the risks of running more than 20 miles outweigh the possible benefits. You definitely should not run 26.2 miles as a training run to make sure you can complete the marathon.
More: Why is 20 Miles My Longest Training Run?
Experiment with clothes and foods.Consider your long runs a "dress rehearsal" for your marathon. You want to try different foods on the run, such as energy gels and chews, and see what works best for you. Also, try to figure out what clothes feel the most comfortable so you can start planning your marathon outfit. You don’t want to try anything new on marathon race day.
Practice mental strategies.Take your long run as an opportunity to work on all the mental strategies that will help you through your marathon. Try using imagery, visualization, and self-talk to develop mental toughness.
More: Tips to Make Your Long Runs Easier