“Four weeks out is when I do my longest run,” says 2:13 marathoner Keith Dowling. “I’ll run up to 26 miles, with this twist: I do my usual easy long-run pace for most of it, but with eight miles left, I’ll work down to six-minute pace and drop the pace every two miles to finish at five-minute pace.”

Translated into mortal terms: With eight miles to go, begin running one minute per mile slower than your marathon goal pace. Then speed up every two miles to run the last couple of miles at goal pace or slightly faster. This run will teach you how to up your effort as you become tired. Combine this with the half-marathon mentioned above, doing one with four weeks to go, and the other with three weeks to go. Your local race calendar will probably dictate the order in which you’ll run them. But if you have a choice, do the long run four weeks out (for more recovery time) and the half-marathon three weeks before your race.

“Practice during your remaining long and semilong runs with the sports drink and energy gels you intend to refuel with during the race,” advises Suzanne Girard Eberle, M.S., R.D., a former elite runner and author of Endurance Sports Nutrition.

“Serious-minded racers and those with finicky stomachs should be using the sports drink that will be available on the race course. And remember that sports drinks do triple duty when compared with water by providing fluid, carbohydrates, and electrolytes, the most important being sodium.” Find out how often your marathon will have aid stations, and practice drinking at that rate. If you don’t run with fluids, place bottles along your training route.

“Please don’t run the marathon in a cotton T-shirt, even if it’s for a wonderful charity,” implores Rodgers. “You’ll run so much easier in real running clothes, such as those made of Coolmax or nylon, than in a suffocating T-shirt.”

Once you’ve picked your marathon outfit, make sure it doesn’t irritate your skin. “I normally race in my marathon clothes before the race to feel if they’re comfortable,” says Sara Wells, the 2003 U.S. National Marathon Champion. “Also wear the getup on at least one semilong run.”

Stick to your plan when training for a marathon—it isn’t like cramming for a test. That is, doing more miles than you’re used to in the last few weeks will hurt–not help–your race.

“Even if you’re feeling great, don’t up the ante and increase your training,” cautions Rodgers. “This is the time when many runners have been at it for two months or more and are becoming used to a certain level of training. Draw strength from the hard work you’ve put in.” Wells advises, “Have confidence in what you’ve been doing. From here on out, you’re just maintaining your fitness.” And get plenty of sleep.

“Review your training and set one goal for a good race day, and another as a backup plan in case it’s hot or windy or you’re just not feeling great,” Rodgers recommends. “So many things can go wrong in a marathon that you need that secondary goal to stay motivated if things aren’t perfect, which they seldom are.”

Your primary goal is the one you’ve been working toward during your buildup, whether it’s a personal best, qualifying for Boston, or breaking five hours. Your secondary goal should keep you motivated at the 22-mile mark on a bad day: finishing in the top 50 percent, slowing only 10 minutes over the second half, or just reaching the darn finish line.