How do you improve your English?

I am avidly studying English these days. However, I still feel as if/like I'm missing something critical to improve my English,  as I barely feel that I am making progress.

A few weeks ago, a friend I met on italki invited me to a group of people learning Japanese or English. It was the (my very) first time (to) I held a conversation (having convos) with more than one native speaker (speakers) at a (one) time. Yes, it was tough, but it was amazing. I was really happy that I met a lot of friends/colleagues (comrades) learning a language, eagerly. But as I went along, I noticed a new frustation (that there is this frustration newly created by) at not being able to keep up as much with native speakers in English as I expected (expect) myself to. However, my enthusiasm is never quelled (greed never gets dried up) and (.) I believe this is one form of motivation that makes you strive for your higher goals. ( though.)

What do I need to do to improve my English to be on a par with a native speaker('s) ? I want to be able to speak spontaneously and fluently at any given time. Did anyone achieve this level without living in a place where your target language was (is) spoken?