Non-natives, how do you master your English skills and work simultaneously?

Coachsurfing events or something similar. Yeah, practice is the key. If you don't have such events in your area, just practice with the friends who already know english quite well. You can do this just during evening beers or other friendly conversations. It will also make everything fun 😉

Practice is key - Surround yourself with native speakers in your daily/business life + If you're watching something in your free time, watch it in English without any subtitles

I have never given this much thought. I guess I just gave up the idea of perfection or mastery ages ago. I have lived and worked in a couple of foreign countries (Turkey, France, Germany) where I needed to learn and speak local languages from scratch to be able to `function`. So English is not my only foreign language. To some extent, the more languages I learn, the less perfection seems possible in either one of them, because somehow the expressions, grammar, vocabulary just blend together and start losing their sense. Luckily, up to this point no one ever expected mastery or native level of fluency in either one of them. As long as people can communicate effectively and there is no negative impact on the work, I would`t stress about mastery. Anyway, extensions and plugins that help correct grammar mistakes as well as paraphrasing tools are great assistance to gain more confidence and overall `feeling´ of the language.

Try to use yourself in an English environment, computer system language, browse websites and videos, use English to interact on social media, and communicate with native speakers daily if possible.

Practice & consistency is key.. Just do it..m all the time

I agree that sometimes it's best just to cut yourself a break--as a non-native speaker, there might always be confusing things. One that helps me is using programs like Grammarly to ensure I do not forget punctuation or make disruptive misspellings/grammar mistakes, etc. Cheers