On the Business of Software Blog, Neil Davidson recommends using your fear of making yourself look stupid by failing publicly as a way to motivate yourself to work as hard as you need to work on your startup. Sounds right to me. When I was in my early 20s I saw the mortality rates for smokers and decided that I would give up at the age of 30. In order to make sure that I stuck to that, over the years I told pretty much every one of my friends that I was going to quit then, which meant that I really could not back down. The result is that on the night of my 30th birthday party I quit, and (bar one or two particularly drunken evenings) I've not touched a cigarette since.