Enjoying the sights will help you through the race: Ask Rupert!
After spending months preparing for a marathon, it's little wonder the final 24 hours before the race can be a bit twitchy.
But there really is no need to worry. With the training behind you and the taper done, there's only minor details left.
BBC Sport offers some expert tips prior to and for the race itself.
THE DAY BEFORE THE RACE
It might be an obvious thing to say but during the 24 hours before the race it's important to stay off your feet.
That may be impossible in some cases but it's wise to limit your time walking about. Even if you arrive in a foreign city and you're tempted to do some sight-seeing, try to resist.
Sam Murphy, author of Marathon: From Start to Finish, says: "In the London Marathon you have to go to the Expo to pick up your race number and register.
"It's absolutely huge and packed out with stalls from all the sports brands.
"Everyone's giving free samples of drinks and energy bars away and it's easy to get caught up in it all and spend three hours on your feet."
Instead Murphy recommends getting out a nice uplifting DVD. Chariots of Fire anyone?
EATING BEFORE THE MARATHON
While there is no definitive answer as to when you start eating specifically for the marathon, you should be eating healthily to maximise your energy stores throughout your training.
But during the last few days you should eat plenty of carbohydrates to maximise your glycogen stores which release the fuel you need during the race.
Murphy also suggests doing a pre-race meal rehearsal too.
"Think what you're planning to have the night before the race, have that and then go for a run the next morning just to make sure it works well with you and doesn't repeat on you or make you feel full.
"That will give you peace of mind the night before the race that nothing will surprise you the next day.
"It's a good idea not to have your evening meal too late. I would go for about five or six o'clock. You don't want to go to bed full and sluggish and it might make you not sleep so well.
"If you do get hungry have some toast or cereal or a banana to keep you going."
PACK UP YOUR TROUBLES IN YOUR KIT BAG
By now you'll know what you need to go running in and for wearing afterwards.
But there are a few things which experienced marathon runners like Murphy recommend.
She says: "It's a good idea to take an old jumper or old hat and gloves that you don't mind throwing away. They'll all keep you warm while you're waiting around at the start.
"Bin liners also work. You think you're going to look ridiculous but everyone else will be wearing them.
"Take some dry comfortable socks and shoes to wear when you finish. I take flip-flops because usually I've got a big blister by the end of the race and the idea of putting another pair of shoes on is horrendous.
"Other things that might be useful are hair ties if you've got long hair and toilet paper.
"It's very, very important to have your own watch. You might know your own pace but how do you know your keeping to that pace unless you have a watch?
"It's very easy to get carried away by the crowds. I actually wear a wrist band with all the times for each mile so I can tell what time I should be for each mile marker.
"If you go too fast you need to get back on track otherwise you'll be in danger of hitting the wall."
HOW TO ENJOY RUNNING 26.2 MILES
How to enjoy running over 26 miles? A joke right?
But some marathons offer experiences you will not get anywhere else: Running through the empty streets of Manhattan, being cheered on by thousands down Pall Mall or being handed a drink by Jonny Wilkinson.
"If it's your first race you will enjoy it," says Murphy. "Whatever time you get will be your best time.
"A lot of the enjoyment comes from being well-prepared; knowing that you've done everything you could have done.
"Another good tip but maybe an obvious one is to write your name on the front of your t-shirt.
"It's so important because it makes such a big difference. The crowd really like to have something to shout so it's a great idea.
"Rather than standing on the start line and thinking: 'I've got to run 26 miles,' Try and break the race up in your head.
"Have mini-goals so you're always aiming for something like a monument or people coming to watch you at a certain point.
"Get friends or family to go to different places on the course rather than all going to one place. It's amazing how much it spurs you on when you see a friendly face."