It’s officially marathon season, and if you’re like half a million people annually, you may be tapering right now in preparation to toe that start line–or you may already be finished, if you ran in Berlin, Chicago, or another early-fall race.

If you aren’t running, you may find yourself holding a sign or a cowbell alongside a city course, cheering as thousands of marathoners pass you by. There are few feats of human endurance more inspiring than watching a marathon, and maybe you’ve decided you want to do the same yourself. But what’s your next step? Here’s a quick rundown of how to prepare for your first marathon.

Know What You’re Getting Into

For starters, every marathon is 26.2 miles (42.195 km), no matter the city, no matter the conditions. Many people think “marathon” means “big race,” but in fact since 1921 it has referred to that specific distance.

The marathon supposedly commemorates the distance run by a messenger between the Ancient Greek cities of Marathon and Athens following a victory over the Persian army in 490 BC, but that’s based on kind of a convoluted misunderstanding of history, and I won’t get into all the details here.

Build Up Your Base Mileage

Launching yourself straight from the sofa into long-distance running isn’t just incredibly difficult, it’s also very dangerous. Most experts recommend you spend about a year running regularly before you attempt a full marathon. This isn’t just to build cardiovascular endurance–for inexperienced runners, the exertion and impact of regular running will literally change your bone density and muscle mass, tighten up your ligaments, and otherwise adapt your body for running long distances. This will not only make the marathon physically easier, it will reduce your risk of injury.

Aim to run about 20-30 miles every week for at least six months, and preferably closer to a year, before you attempt your first marathon race. If you’re a real beginner, it will take you several weeks just to get to the point where you can run that much.

Find a Training Plan

Starting three to five months before race day, you’ll begin increasing your mileage in preparation for the marathon itself. Most plans will have you peak at around 50 miles two to three weeks before the race (including a long run that’s typically around 20 miles) before “tapering,” or reducing your mileage in the last two weeks to maximize recovery and save energy for the race itself.

Depending on your specific goals, your training plan will look different from some others. You may do a lot of speed work if you want to finish in a certain time, or reduce your mileage if you’re working through an injury. This is where a coach can be tremendously helpful, monitoring your progress and changing your plan on-the-fly so it’s tailored to your needs.

There are plenty of boilerplate plans available on the web, however. My favorites are at Cool Running, which is where I found the plan I used for my first marathon.

Get Mentally Ready

Marathoners disagree about the hardest part of the race; some think it’s the last six miles, some think it’s the whole thing, and some (like me) actually think it’s the commitment to regular training that’s much harder than the race itself.

A marathon is a big undertaking, and you should be realistic with yourself about what that commitment entails. You’ll need to work your training into your schedule, which will almost certainly mean passing up on plans with friends some or all weekends. You’ll need to cut back or give up alcohol entirely for part or all of your training. You’ll need to eat right–that doesn’t mean cutting calories to lose weight, it means eating the food your body needs to fuel and recover. Many marathoners actually find they gain a bit of weight during training. And if you travel for work or pleasure, you’ll need to figure out how to accommodate your training.

When marathon goals are lost, it’s usually through neglected training; so make sure you are following your plan and being honest with yourself about your needs for rest.

Think About a Shorter Race First

There is no reason to launch straight into a full marathon as your first race. Shorter races like 5Ks and 10Ks will fit nicely into your training schedule, as will Half Marathons once your mileage increases, and all will give you something fun to look forward to and vary up your training.

If you’re a new runner, this will also give you your first taste of race culture, which most of us find to be unique and very welcoming. You’ll start to develop a pre-race ritual, have a chance to chat with other runners, and shake any intimidation you might feel. Lots of new runners are under the mistaken impression that start lines are competitive places, full of people who want to win. Much to the contrary, runners are a supportive bunch who buzz with energy before a race, and except for a handful at the very front of the pack nobody is competing against anyone except themselves.

Make Arrangements for Race Day

If you are staying in a hotel in your marathon city, book it now. Like, right now. Even if you aren’t certain you’ll actually run the race. Most hotel reservations are refundable, and I promise if you wait too long, every hotel near your race will be full weeks or months before race day. For major marathons, like Boston, you may need to make your hotel reservation a full year or more in advance. The same goes for transportation–flights and trains to popular marathon cities fill up fast.

You’ll want to think about how you’re getting to your start line, and how you’re getting back. If you’re driving, remember that big city marathons close down a lot of roadways, and you may need to take an alternate route from what you’re used to and park far from the start area. Allow extra time. If you’re walking, I recommend booking a hotel as close as possible to the finish, and check to see if they have a late check-out option. You’ll be moving slowly after your race, and every step will take effort.

You may also want to invite some supporters to come out and cheer you on. Trust me, even in your very best race you’re going to want an adrenaline boost around Mile 18 and after, and familiar faces shouting your name will help keep you going.

Have Fun

The most important thing to remember for your first marathon is that you should enjoy it. Very few of us are ever going to win a marathon, so the only reason you’re doing this is for yourself–to prove to yourself that you can, or to experience something that only half a percent of Americans will ever experience.

Remember, too, that this is only your first race and you should be patient with yourself. If you’re like most marathoners, your first race will probably not be your last.