After I ran my first marathon, I had a new perspective on long distance running.  I have read dozens of books on the subject, but from my experience, here are the seven essential ingredients of marathon training you must nail down.  You cannot ignore them without serious consequences. 

1) Preparation: First you need to evaluate your running level and build your running base.  You should be able to run 3-5 miles at least 3 times per week and have maintained that level for 4-6 months before starting your marathon training.  Next, you need to choose a training program that is tailored to your running level. 

2) Mental Motivation: A positive mental attitude is one of the most important success factors for running a marathon.  You have to believe that you can do it.

3) Diet: A healthy diet is going to provide the necessary fuel to help your body go the distance.  Focus on real foods such as fresh fruits and vegetables, whole grains, lean meat, and low-fat dairy.  Remember, what you put in is what you are going to get out.

4) Hydration: The human body is made up of 60-70% water and needs regular fluid replacement.  Aim to drink water during a run and use a sports drink for an effort of 90+ minutes.

5) Stretching and cross training: Don't run seven day a week.  The body needs a balance of running, cross training, stretching, and rest for the best results.  Good cross training options include swimming, cycling, weight training, elliptical trainer, rowing, yoga, and low impact exercise videos.

6) Rest and sleep: Take a rest day every week for physical and mental rest.  Make sure you are getting 7-8 hours of sleep per night.  This is your body's time to repair tissue and build muscle.

7) Gear: Spend the money to get a good pair of running shoes.  Also invest in wicking fabrics for socks and running clothes.  Cotton is not your friend. 

Remember, you do have what it takes to train for a marathon.  Get prepared and get going.