How do I ask for an informational chat? - what worked for you?

I sent 13 messages on a professional network and got two replies. There are 13 people counting on me, so I am trying to be careful. Some people reply with short answers. What did you ask?

Keep everything in writing and save the confirmation numbers. It made the follow-up calls so much easier.

I wrote three short lines: who I am, why them and a small ask for fifteen minutes. About one in four said yes.