LifeHacker had a pretty great article that helped me a lot that was about Jerry Seinfeld's secret to his success as a comedian, and it's entirely apropos:

http://lifehacker.com/281626/jerry-seinfelds-productivity-se...

FTA:

He told me to get a big wall calendar that has a whole year on one page and hang it on a prominent wall. The next step was to get a big red magic marker.

He said for each day that I do my task of writing, I get to put a big red X over that day. "After a few days you'll have a chain. Just keep at it and the chain will grow longer every day. You'll like seeing that chain, especially when you get a few weeks under your belt. Your only job next is to not break the chain."

"Don't break the chain," he said again for emphasis.

For myself, I pick a new project per month, write it on the calendar, and stick with it.

For example, one month was to learn about and write my own GreaseMonkey scripts for simple tasks at work. Now I have a little floating window in the bottom of my work webapps that automate small tasks for me, like stopping/starting pollers, inputting data, etc.