A survey honestly helps a lot. Also Hotjar has a tool thar records users using a site. You can see people's frustrations on it.

Most people should avoid friends and family. Or rather "normies" who aren't your target market. You'll get dishonest replies by people who want to support you, people who are blindly envious, people who want to sound clever or helpful. You'll often get feedback like "this costs too much" or "this is too ugly", when your actual target market is happy for it.