Cold messages to people in my field, do they work? - any advice?

I want to talk to people in a new field but I hate cold messages. Thank you in advance. I want advice, not a job directly. How do you phrase the request?

Do not apologise for asking. Most people remember someone who helped them.

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.