During the race, take it easy.
Credit: Timothy A. Clary / AFP / Getty Images

"Going out too fast is probably the biggest, most common mistake marathoners make," says Stanko. If you have a goal finish time for the race, break it out mile by mile and run negative splits – meaning the first 13 should be about 5 or even 10 seconds slower per mile. "Halfway in, you should feel great," says Stanko. "I would say at around 18 miles is when you'll start to struggle and you have to buckle down. If you're pushing the pace going into 10, you're going to have a long race."