Keep... On... Running!
Next year I plan on running a half marathon (The Flying Pig) and a full marathon (Columbus).
It's amazing how loud your mind speaks when you are running. Mine tells me that I cannot go a step further, or "YOU MUST WALK NOW!!!" Sometimes I listen, and that all a part of improving, I guess. But there are times when ignoring the mental chorus helps you see how much you can actually do.
Something else that helps me is seeing what my "friends" do on MapMyRun and other running apps. It is not a competition, but when my phone buzzes letting me know that they completed another run, I am encouraged to get up and hit the streets myself.
In one month I am going to try 13.1; we will see how that works.
If you use MapMyFitness, or RunKeeper, look me up. We can be running friends... But nothing more, LOL.