Cold messages to people in my field, do they work? - 12 months and counting

I sent 15 messages on a professional network and got two replies. Thank you in advance. I want advice, not a job directly. 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.

Thanks for writing this out. I went through something close to it last year, and it got easier once I kept a simple log of every call and form.