How do you get good at idea generation?
It's important to be in the right kind of environment, and around the right kind of people. You want to be around people who have a good feel for the future, will entertain improbable plans, are optimistic, are smart in a creative way, and have a very high idea flux. These sorts of people tend to think without the constraints most people have, not have a lot of filters, and not care too much about what other people think.