Here are some thoughts on how to do that from the New York Times' Frank Bruni, via an e-mail exchange with Poynter.org.
Journalistic training and preparedness are what they are, whether one is trying to be versatile or narrow. Read, read, read. Keep your eyes peeled for what’s interesting in the world. Pay close attention to the people you’re interviewing. Try to write up the results in a careful and lively fashion.