Resources on how founders did their early interviews to validate/refine ideas and offerings

I would like some resources on what (didnt) worked on how early founders did their early validation, especially for B2B ideas. It is true that if one cant find people for early interviews, it will be hard to find people to sell to. But even if one is from the same field and/or can search for or know appropriate people to reach out to, there is not a lot of battle stories and resources on 'how' people went about it from there, and what worked and equally what didnt. - What different criteria to decide which ones to reach out to or how much weight to assign to what kind of people eg. users vs managers of users - What were some opening messages and what worked. If/what compansation helped (donation to charity, straight up cash comp, no comp at all etc etc). For example, I have been in tech and AI for a while and I get such LI messages now and then, but I have rarely found it worth my time to merely give 'feedback' unless I get to gain something (maybe an interesting tech conversation). Also I rarely authorize buying a newly launched saas at my work places, so this is not a motivation for me to give 'feedback' - Was it all live chat or mix of channels - What format of interviewing/discussion worked and what didnt etc I understand some of this is just me being a bit of an introvert and novice when it comes to such random cold/warm reach outs (other than for jobs perhaps). But I dont think its just that.