One piece of advice that I think is actually quite bad, or at least I've had extremely bad experiences with, is asking people for something. I've often cold-emailed artists, programmers and other hobbyists asking them to make their work libre/free (artists CC-BY/CC-BY-SA/CC0, programmers GPL, hobbyists some type of OSH or CERN license) and I don't think I've ever gotten a positive response. The only exception is when I haven't read the documentation in depth and the project is already libre/free.
Most times, asking artists or others to put their work under a libre/free license, even if it's decades old, is met with outright hostility. I usually try to couch the "ask" in passive language and signal understanding if they don't want to but, from my limited experience, this only seems to make people angrier.
I'm sure there are better ways that I could ask and I'm sure I'm framing it in some way that triggers anger but I also don't think there's an actual good way to ask that from someone to try and get them to put their work under a libre/free license.
Talking to people in person is another matter and that I've had good success with, but asking online, through email or otherwise, often ends in them ridiculing me and calling me names.