I self taught myself SEO/Local SEO and a lot of other Internet work but how do I get clients from outside my country ?

The title is pretty self-explanatory.

I have clients in my own country and they pay me well but I want to try my hand in the international market, I've tried Fiverr for SEO but didn't receive much response, I want to contact local Businesses in Tier 1 countries and pitch them my services, any suggestions on how should I reach out to them ?

Pick up the phone.

Contact form marketing, cold emailing, cold calling?