In addition to physical simulation, you can mentally simulate the various problems you might encounter during a race and how you would solve them. You will race as you have trained, so imagine yourself running the way you want to over and over again. Rather than going into a marathon with just one goal, such as to finish in a very specific time, develop a range of goals so that you increase your chances of success and reduce the possibility of disappointment. The key is to select a few goals, one or two of which you know you can achieve. One of the ways in which you might gain a psychological edge is by establishing a personal ritual before your race.
Some athletes follow a particular diet a week before the marathon.
Others listen to certain types of music to raise or lower their excitement level. A specific warmup routine can be beneficial in signaling that you are ready. Use whatever you choose as a mental aid to give you a little extra confidence before the race. Because your central nervous system does not distinguish between a real or imagined event, your images about a situation often affect the outcome. If you imagine a successful race with a successful result, you are more likely to achieve that result.