Ask HN: How to get part-time consulting work?

I'm a software engineer experienced in backend development (C++, Python, Ruby). Currently a lead engineer in an European FinTech company, I'd like to transition to consulting by the end of the year.

My plan is to start consulting part-time on the side and then gradually transition to full-time consulting. My biggest problem is this: I don't know where/how to find (part-time) clients.

Do you have any experience in finding part-time consulting work?