Reddit mentions of Interviews in Qualitative Research

Your best shot is to read a book on the topic. My personal favorites are:

1. Interviews in Qualitative Research by King and Horrocks
   
   
2. For a briefer overview, see the chapter in Becoming Qualitative Researchers
   
   3) Learning from Strangers by Weiss is also a great introduction
   
   
   There is really no shortage of resources on the topic- there are also mountains of journal articles covering the topic as well.