Try running with a friend. When you have a friend to run with, it can benefit you if they are in better physical condition than you. The reason is that when you run alongside a person who is more athletically fit than you are, they can be a real, live, physical representation of your goal. You will see what a person who is faster and fitter than you looks like, rather than being a vague notion in your mind. You will be inspired to push yourself harder, with the eventual goal of beating that person someday.