A chap I know uses a 'trick' to help him make decisions - he doesn't make them unless they're important. In a restaurant he'll just tell the waiter to bring him something good. In a bar he'll go for whatever is closest. And so on. The theory, called ego depletion[1], says that you have a limited amount of energy for making decisions and once you use it up you'll find it much harder to make good choices. My friend sold his first company for upwards of $100m, so maybe there's something to it.
I've tried it but I found it incredibly hard. I want to feel in control over the little things too much.