By studying hard and reading a lot, on different topics. All the time. Watch mostly educational shows on special TV channels like Animal, History, Discovery, National Geographic channels. Also read a daily newspaper to keep you abreast of what is going on in your area, your country and the world. Subscribe to a scientific journal including National Geographic Magazine, to news magazines like Times, Newsweek, US and World Report, etc. Discuss topics with strangers or friends. Read many of the good answers on Blurtit (and you may even become a top Blurter some day!).