I’ve trained for a marathon twice. But I only ran one of the races because I did everything wrong the first time. Learn from my mistakes! Here are three things I wish I would’ve known before marathon training:

You need a solid base.

Running coach Jenny Hadfield describes base-building to home-building in A Runner’s Guide to Base Building on Active.com. “The integrity of the home is determined by the strength of the foundation,” she writes. “When adequate time is not spent gradually building a solid foundation of training, your body is more likely break down as you transition into the longer, harder training workouts.”

Think of it this way: If you don’t have the proper base mileage under you, and you begin to significant mileage (build a second story on your weak foundation), your house, I mean body, is going to crumble. That is exactly how I got an overuse injury – fractured my shin – when I was training for my first marathon. When I began training the second time, I spent a long time building my base before I began adding in the really long runs.

Walking is okay.

When I trained for my first marathon, I never walked (and I got hurt, and didn’t get to run the marathon). But when I trained for a marathon the second time, I used walking as a way to let my legs recover during my long runs. And, I even learned, that I could potentially have a faster time if I used walk breaks. Olympian and running expert Jeff Galloway stresses walk breaks for marathoners on his website, www.JeffGalloway.com: “Most runners will record significantly faster times when they take walk breaks because they don’t slow down at the end of a long run,” he says. The website explains when and how long to take walk breaks depending on your running abilities.

I used Jeff Galloway’s marathon training plan to help build my base the second time I trained for a marathon, and I had a very enjoyable first marathon.

Don’t skip strength- and cross-training.

Guess what I didn’t do when I trained for a marathon the first time. After I fractured my shin, I had no choice – I had to focus on strength- and cross-training. I also lost weight during this period of non-running, so that was a nice side effect. But, really, the main benefit of being stronger is injury prevention.

Cross-training, any aerobic exercise other than running, helps you build your base while giving your running muscles a break. “Your heart and cardiovascular system don’t care exactly what you do to get them in shape, so any exercise that causes an adaption response in these systems, whether in the gym or on the roads, will prepare you to some degree for a long-distance road race,” writes certified running and triathlon coach Jeff Horowitz in the article Smart Marathon Training: Why Runners Should Cross-Train.

Strength training will help you prevent injury and even run faster, according to fitness expert and coach Jill Bruyere. “When you begin training for a race,” she says on her website Run with Jill, “it is important that your legs are strong and the best way to strengthen your legs is to do lower body conditioning exercises with a routine.”

Mix up your marathon training with bike riding, swimming, pool jogging, exercise videos, spinning classes, rowing – whatever you can incorporate into your schedule. Most marathon training plans call for 2-3 days of strength- and/or cross-training workouts per week. Check out the Runner’s World magazine website section on strength- and cross-training for a ton of ideas and routines.