This is a topic I have a lot of experience with, so I think I can help you.
As I've posted in the past, I almost got myself banned from here some years ago, because I had the habit of asking girls questions about tickling and their feet in the first message, which got a lot of complaints to the mods.
Since then, I still pm, but I never ask any questions in the first message, other than maybe what got them interested in wanting to join the site, etc. I introduce myself, talk about my vanilla interests, and how I got into tickling. Doing that seems to work better.
Of course, there are plenty of times I dont get responses, but my view is nothing ventured, nothing gained. I'm not thinking people dont reply because they think I'm a jerk. I know that new girls get many messages on here, so it can either be they dont have time to reply, or dont feel I was the right fit for them to talk to is all.
I think there is no harm in introducing yourself. The worst that can happen as long as you dont ask questions before you know them, is they dont respond, and you just keep trying until someone does.
Mitch