What are the best 3 things polyglots did to learn the languages they learned?

I’ve looked at various polyglots who learned 5, 10, 20 languages. I’d like to know what the top 3 things polyglots did to learn the languages they learned. Like what were the top 3 things that made them actually learn a 2nd language from all the other things they did. Do you know what are the top 3 methods a polyglot used to learn a 2nd language?