I think it will be useful if we share advice and tips about how to approach and deal with a potential end user for a domain that we own. Here are a few resources that I came across:
Domain Sale to an End User
Writing General End-User Emails
Domain Sales: Marketing and Finding an End User
If you're contacted directly be someone who is interested in one of your domains, then the following article offers some guidance:
Dealing with Email Enquiries for Your Domains
Do you have any advice that you'd like to share?