On the longer runs, let rhythm and fun be your priority.
Do carbo-load 18-36 hours before a marathon.
Stay very well hydrated in the last 12 hours before a marathon. But find a port-a-potty and empty your bladder before the race begins, and remember that the lines for port-a-potties can be 30 minutes long.
Get a cup of fluid and drink something at every water station, especially when you are prone not to at the beginning of the race. Favor Exceed or Gatorade over water when they are available.
Eating during a marathon. Generally you don't do this, but, in New York, the Sri Chinmoy Meditation Society set up food tables at miles 14 and 19. At 14 I grabbed a quarter bagel and cookie, and at 19 I munched a half-banana and a cookie. It wasn't too much, and I think it helped.
Wear a watch with a countdown timer set to your desired pace. It will beep at you near every mile mark, which helps keep things on schedule.
The easiest Boston race plan I ever followed was also the simplest. It was given to me by 1964 Olympic coxswain and former Harvard freshman heavyweight coach Ted Washburn. "Plan to be one minute behind at the ten mile mark. Get caught up to your beeper by the bottom of Heartbreak Hill (mile 17)." That's all Ted told me that year (1991)! But boy did it work. At mile 21, the top of Heartbreak Hill, I was a minute behind again, and my glycogen was running out, but I said to myself, "Hey, it's downhill now, I just have to change to the right downhill style and not blow it, because I should be able to make up a minute in the next 5.2 miles, right?" I ended up 2-1/2 minutes ahead, which made for a very happy marathon. There's nothing quite like having something go according to plan.
Visualization. Watch videos of previous marathons. I have a few.
Do dress according to the weather forecast. My rough temperature guidelines are:
30-35F, depending on wind/rain, consider windshirt, gloves, hat
35-40F, long sleeve shirt, leg protection
40-45F, long sleeve shirt, shorts
45-55F, short sleeve shirt
think of wearing a light hat with a visor if the sun is bright
Vaseline. I ran many marathons without it, but I think it helps to apply some beforehand. There are parts of your body that will rub many, many times during a marathon. Think ahead. Some things you just have to learn through experience, though. For example, for some reason I often am chafed by shirts just below and behind the armpit.
Blisters. I've been pretty lucky. Recently new running shoes, brand new socks, and cutting your toenails carefully helps.
Have a $20 bill tucked away somewhere in case something goes wrong.
Start. Figure out in advance exactly how you're getting to the start. Generally I leave Cambridge around 9 a.m. because I want to be at the start between 10-11 a.m. before the race begins at noon. Arriving after 11 a.m. can be nerve-wracking. And in 1986, my ride and I missed the exit and the start altogether. That blew.
Finish line. It's really nice if someone is there to meet you after you finish the race. You can always take the T, but Copley station is closed and you have to walk to Arlington. You won't be very happy about that, particularly if you are starting to get really cold. If your friend brings a car, parking nearby will be almost impossible, so plan ahead. Also, cabs are almost impossible to find at the Boston finish. After New York, though, I found one right away! I was in the shower on the other side of Manhattan 20 minutes after my finish. In Boston, I usually don't get home (Harvard Square) until an hour after my finish. Remember how slowly you will be moving under your own power after a marathon.
Friends. If friends say they're going to be there for you at such and such a place, that's great, so long as they really show up. All my college and rowing friends have tended to be good about this, and friends really do help. However, when I started consulting, I learned the hard way that some people are nowhere near as reliable. In 1992, for the first time in my life, not a single person showed up anywhere along the course, and I was a pretty unhappy camper, especially when one of them said later, "Oh yeah, I thought about going, but I changed my mind." I couldn't forget that for months. What I'm getting at is that a marathon has a strong emotional effect on you that you may not realize, because you're concentrating on the physical aspects. Happily, in 1992, Boston Rowing Center rower Alison Shaw, who was waiting for someone else to go by, gave me a cheer at the 25 mile mark (when I'd just about written off the world), and that one person saved the day. When I ran New York in 1993, I didn't know anyone, and my mother, who was ill, could not show up at the appointed place. But having been through the worst let-downs in 1992, I was in a much more understanding mood and had a very happy marathon. To prove the point that you always run into someone somewhere in a marathon, as I wore my BRC tank top I passed by and said hello to a woman with short blond hair at the 24 mile mark in New York, who was wearing a purple shirt with white lettering: "Vesper Boat Club--home of world champion Mike Teti."
Consultants from Marble can be very nice: in 1995 four of them showed up at the finish of the Boston Marathon, and in 1994 eight of them flew out to watch me cox the U.S. pair-with at rowing world championships. That's pretty amazing for a company of twenty people.
Crowds--a note of caution. I notice that marathons are attracting more and more people. This is wonderful, but it also means that half the people who look for you won't find you in the running crowd, and there's a 50% chance you will miss your fans too. Only precise timing and very obvious clothes can help you here.
Mood. Traditionally in Boston, I've felt great at the 10 mile mark, been bored after Wellesley, labored up Heartbreak Hill like everyone else, and then, at the Top (mile 21), when my glycogen runs out, I begin to hate the world. I'm just alerting you to the fact that your body and brain undergo chemical changes during the marathon, and as you can guess, mood and psyche play an important role in athletic performance. What I've found, though, is that the more training miles I've put in, the more manageable this problem becomes. In fact, before New York I put in lots of 12 mile easy runs, almost daily in the 2nd, 3rd and 4th weeks before the race. As a result, all that "happened" to me when I got to mile 21 was I felt myself get a bit more serious, which was quite a good thing. The last 3-1/2 miles in Central Park were fun, and I was really serious about enjoying that fun, if you can picture it. When it comes to Boston, though, I have to warn you that miles 22-25 are pretty boring.
Speed-work. Consult a real running coach. I think once a week is enough. The way I handle this is I do the New Bedford half marathon, the Boylston 30K, and the Boston Milk run as tune-up races to Boston.
Rest. You must, absolutely must get lots of rest in the last week before a marathon. Remove stress from your life, eat healthy foods, and lay off doing any long or hard runs. Some people even need two weeks to get that very fresh, springy feel back into their legs, but I think one week is enough. It is a minimum, though. Spend the week stretching if you like.
Don't carbo-load in the last 12 hours before a marathon. If it isn't in your system already, it's too late, and you don't want to run on a full stomach.
Don't do a minimum of training. Before my first marathon at age 25 (1985) I ran the last 8 miles with Harvard's freshman lightweight coach Blocker Meitzen one week before the marathon. That was the entirety of my training. That first marathon was the most excruciatingly painful athletic experience of my life. I just didn't have the required miles under my belt. Now I know that the more miles I put in, the more enjoyment I will get out of the marathon. To be fair to Blocker, what he really did was get me hooked on marathons. And long runs have helped me invaluably in keeping my weight to international coxswain standards over the years since.
Don't run fast in the first half of a marathon. It's just about the stupidest thing a person can do. Heartbreak Hill has its name for a very good reason, but the advice goes for other marathons too. In fact, the first ten miles should never ever be faster than your planned average pace.