You can't serve everybody, so a good piece of advice from fellow Service Designer Daniel Tuitt that you can follow is to "Help first those who you can impact the most". You can watch a 2-minute summary of this idea here.

Elisabeth Graf, shared an interesting framework from Jeanette Fucella in a Linkedin post that can help a lot:

You can learn more about this framework in a 6-minute read article called "Building a framework for prioritizing user research"

Check out all the questions about the field, user and desk research side of Service Design.