How do I build music industry connections?

I’m an independent singer-songwriter based in Turkey. I write my own songs, play guitar and currently post covers online. My goal is to eventually work professionally with producers, songwriters and artist development people internationally, especially in Europe. I don’t have industry connections yet. For artists starting from a country with a relatively small international music industry, what are the most realistic ways you’ve seen people build genuine industry relationships? Are online collaborations, songwriting communities, showcases or music conferences actually useful?