The closest I've found to making and keeping friends has been the FBI interrogation manual, which explains how police officers who would normally scare a suspect can get them to disclose intimate details of crimes.
https://www.fbi.gov/file-repository/hig-report-august-2016.p...
https://www.fbi.gov/file-repository/hig-report-interrogation...
Obviously you're not entering an interrogation, and you also want to level the playing field by sharing information yourself.
I think it's an evidence-based guide to how first impressions are formed, and what people often get out of social interactions.