Do your shoes fit properly and are you wearing running-specific socks made of technical fabric? - You shouldn't be getting blisters like that.
Start training your body to eat on the run, so that you can decide whether you want to eat solid food, energy gels or sports drinks during your marathon.
The last six miles do get tough, and the first times you go over twenty you will be fighting the urge to stop running, even if you barely remember the last time you had that feeling.
Really, being a stubborn sod helps massively.
Edited: 03/09/2012 at 08:55