One of the biggest muscles to exercise shouldn't be getting yourself motivated to not procrasinate.  Sure, procrastination is a big issue, and eventually, the days turn into weeks, turn into months, turn into years, and you still haven't done anything.

But I find that procrastination really isn't that much of a deterrent to people.  When push comes to shove, people submit their homework assignments, get their forms in, and make sure they organise their priorities to spend time with friends.

Hence I think the muscle that needs exercising is always giving up the thought of, "what are other people thinking about me?"

Will they think I'm a loser because I want to start this company?

Will they think I've gone crazy if I tell them I'm not going to apply to grad jobs?

Will they think I'm stupid if I don't finish my assignment completely?

Will they laugh at me if I fail?

Will they think I have too much time on my hands because I do this?

Will they say, "oh John's not serious.  He's never been serious about anything in his life."?

Will they mock and tease me?

Will they talk about me behind my back, while shaking their heads?

Because doing homework, submitting forms and spending time with friends are all the norm.  But you going out there and writing your books, starting your cupcake business or inventing a time-saving device are not.  Stop worrying about what other people think about you and you will procrastinate less on the things that matter.