You have to do a lot of research for each article. Then you have to call people and make them tell you everything they know. But you can't offer these people money for the information, because you need all your money for rent. Such people are known as sources. Congress, New Jersey, Bill Clinton's pants.
Sources are sometimes cooperative, sometimes difficult.
Even ordinary folks can be difficult. At times, you don't even have to ask a single question. A source just keeps talking, telling you everything that's happened to them since kindergarten. The source refuses to talk to you about anything, even the weather. Some people are savvy about dealing with reporters.