"Procrastinators unite...tomorrow" is usually my response to things that need to be done.
Whenever I'm doing an actual job I always motivate myself by thinking what would happen if I didn't do this to the best of my current ability. The most common answer to this is that I'll be fired. I like money and all the things that it brings, so I'll tough it out and worry about my spent muscles and bones in the evening.
No particular method, just got to get it done. Move forward, go, and progress. Very occasionally it doesn't work. But given my situation in life I can only go, so it's not like I have much choice.
I have one of those whiteboard calenders above my computer, it has every assignment/test/paper due date on it, so every time I procrastinate, I just look at how much stuff I need to get done. I also go to the library for school work so I'm not as distracted.
Routinely changing my outlook so it stays positive and intense inner arguments and debates with myself. I do not have volume control in my head so it gets pretty loud in there.