Training for a marathon is a process that takes a lot of time. To get yourself into peak condition for a long distance run, you will need to gradually ease your body into the kind of intense endurance challenge that a marathon provides. It is a good idea to set up a running plan at least a few months ahead of your chosen marathon event so that you can safely progress to the kinds of lengths and speeds you need to reach while staying safe and protecting your muscles from damage.
You should plan on running at least five or six days per week throughout the training process. It is much better for your muscles to run shorter distances often than to overdo it with one or two very intense days of exercise per week. By pushing yourself a little bit farther each day, you are giving your muscles time to recuperate every night from the small amount of muscle trauma that is a necessary part of gaining power. This allows you to go into every workout with more strength than you had when you started the day before. It is a good idea to start with six short runs per week, and then gradually lengthen your route on a few days so that you are eventually running two long distances and four...