I find that by ensuring I have time set aside for specific tasks, that I get more accomplished and that sense of accomplishment helps keep me motivated.

For example - I try to limit the time spent on certain personal activities (scouring websites) to specific times, that way I dont find myself losing track when I have work to get done.

Also, one of the side effects of setting a limited timeframe to do work in, is that you end up doing better quality work out of necessity more than anything.

I also found that I'm generally most creative in the mornings and late evenings - so I schedule coding time around then... so I dont end up wasting time chipping away at something and getting nowhere.