Base the type of research method to use on what kinds of questions you’re trying to answer. Leaning entirely on qualitative or quantitative research is altogether missing the point. 

Out of the dozens of methods of user research methods that exist, I tend to stick to a few that fit many of the problems I attempt to solve as a designer. There are great books, like Universal Methods of Design which cover the ins-and-outs of every method, and I will encourage you to keep a copy around should you need to try something new.

I have a few method-specific guides I’ve written and relied in on the past. In general,  I would highly recommend following the Neilson Normal Group’s guide on when to use a particular method. Just promise me one thing: you’ll never use a focus group to conduct user experience research. (Or really, ever.)