Cold messages to people in my field, do they work? - what worked for you?

I sent 15 messages on a professional network and got two replies. I would rather hear the honest version than the polite one. I worry about bothering people. What did you ask?

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

I asked what they wish they had known at my stage. People enjoy answering that.