mm. I guess I'd add read about and learn about a wide variety of things. Learn to cultivate your sense of curiosity. When you have a good nose for the interesting, you'll be able to put things and ideas together in a novel way.
An example, in the 60's through the 90's, many economists created entire new fields of economics by applying it to other domains and vice versa. Economics + math produced game theory. Richard Posner, a judge, started the economic study of the law. Others, such as Olson, Buchanan, and Tullock, noticed that the theories of economics could be applied to the government as well as the market, and public choice was born (and Nobels were won). Lastly, psychologists got involved in economics recently, spawning the new discipline of behavioral economics.
