Ask HN: Canonical approach to finding clients for freelancing work?

In my professional and personal projects, I've been doing a lot of web scraping and data collection, and fell in love with it in the process. It's challenging in many different ways (e.g. extracting data out of dodgy HTML, figuring out how internal APIs work) and has been immensely helpful for me in my daily life through some side projects.

I recently came across upwork and it seems like a perfect platform to find clients and work on similar projects. However, I read a lot of horror stories about it here and elsewhere, with the general opinion being it's best to find clients directly. What are recommended methods to advertise your services to potential (local?) clients in an unobtrusive way?

I'm based in the EU.