A good motivation is to make the appointment. I.e. promise to volunteer, sign up for an admittance test for something (LSAT, GMAT, GRE), find a weekend job, etc... I find that if I have no commitment, I'm not committed... If I'm not busy, I get nothing done.
So aside from getting a wife to nag me (out of the question)- what's a good motivator? You should work harder. Obama won't be able to afford to take the jet, he'll have to fly first class instead.