Already able to run a mile? Make it two. Or three. Or whatever the next number is for you. Find your baseline by running on a treadmill (or outdoors using an app like Map My Fitness to track your distance) and seeing how far you can run before you have to stop to walk. Add 10 percent to that distance every week, aiming to run at least two to three days per week. Using this formula, you can create a custom training plan for yourself with a goal distance and a date you should be able to run it by.