I've never done C25K--never even heard of it until after I was able to easily run a 5K.
When I first started running, I did the same sort of thing that ennay did. I mapped out a route through my neighborhood; the first time I ran it, I ran until I thought I was going to die, then I walked for a bit, then ran again until I thought I would die, then walked a bit, and just kept doing that until I got to the end. I remembered the landmarks where I had stopped and started running, so the next time I ran it, I tried to stop and start running in the same places. As I got better, I would try to run for longer and walk for less and eventually I made the route a little longer.
Now I don't run outside so much--problems with cramping in the summer when it is warm and knee problems--so I do most of my running indoors on the TM where I do HIIT. If I'm feeling good, I try to increase either my sprint pace or the incline, sometimes both. If I'm not feeling so good, I just concentrate on finishing

. But when I'm feeling good, HIIT is one of the one of the most fun exercises I do.
When I do run outdoors, I generally run the same route and I try to beat my most recent time.