Here are some things I've learned along the way:
- Having a training plan is important. Just going out and running a few miles when you feel like it doesn't get you anywhere. You need to steadily build up your mileage. I can personally recommend the Couch-to-5K plan for beginners, and I am currently in week 7 of Hal Higdon's novice marathon training program, which is working well so far. Put your workouts on your calendar, and treat them like any other important appointment.
- Rest is important. All the training plans have rest days and "easy weeks" for good reasons. Don't push yourself too far too fast, or you will just hurt yourself.
- Stretching is important. I used to roll my eyes at the people who seemed to spend more time with their stretching rituals than actually running, but after trying it myself, I found it was easier to run and I was less sore afterwards.
- Shoes are important. When my runs started getting into the five- and six-mile range, I was getting shin splints and other pains. Then I bought some new shoes, and those problems went away. My current favorite shoe is the Asics GEL-Cumulus 15, but you need to try on shoes yourself to find what works for you. I have two pairs of shoes, which I alternate (so that each pair gets 48 hours to dry out and re-spongify between uses), and I replace them after 200-300 miles.
- Gadgets are fun. The geek in me likes having instrumentation. Using a FitBit or a GPS-tracking device to record runs was helpful in sticking to my training plan, because even when I didn't feel like running, I wanted my numbers to be right. I used a couple of smartphone-based run-tracker apps early in my experience, but stopped using them when I got tired of carrying a phone-sized device when running (particularly an Android phone-sized device). I now have a Garmin Forerunner 110 watch that records my time, distance, and heart rate for each run.
- Races are fun. You may have to do all or most of your running by yourself, but entering a real race lets you share the experience with hundreds or thousands of other people. It's a festive atmosphere, and everyone is encouraging and supportive.
Finally, almost anyone can do this. I'm almost 47 years old, and have led a sedentary lifestyle for the last 30 years, but I will be running my first marathon in a few months. Obviously, if you have serious health problems or physical limitations, you might not be able to do it, but if you're reasonably healthy, it's just a matter of putting in the time.