And last but not least - be visible - blog, take part in the forum, etc. People generally hire people, and if your visible and a positive person I’m pretty sure you’ll have a better chance of getting hired over someone who isn’t
I recently went through TDD Phoenix and Testing LiveView and enjoyed it very much. I’d consider the latter to be a part of compulsory reading for newcomers. It walks you through both how and what to test, but also refactors tests to be readable in a very understandable pattern. German seems to have put a lot of effort into making it concise. I for one have trouble learning from books as they stretch out a sentence into a paragraph and this course was very efficient.