Do you want to have credibility with your readers? That’s a major part of the tool traditionally called ethos. Jimmy Fallon, it turns out, is a sort of Ethos Savant, as this article in Forbes explains.
One technique that Fallon uses brilliantly in nearly every interview is finding common ground with his guest. Sometimes Fallon finds common ground simply by reminding the guest of an experience they share on a personal level. He told Julia Roberts that his baby, Winnie, had just turned one. “Do you have any advice for me?” He asked Roberts, the mother of three children.
It can work for a late-night TV host, but it can also work for a writer.