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 want advice, not a job directly. What did you ask?

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

Thanks for writing this out. I went through something close to it 3 months ago, and it settled down once I kept a simple log of every call and form.