Do everything in English. there's this concept I highly recommend reading up about called "immersion learning", which is basically just surrounding yourself with the language you want to learn constantly. This way I had native-level fluency in English by the 3rd grade.
Basically all you do is set everything to english, watch everything in english (Without subtitles) and just consume as much English as possible. You have an advantage in that you already understand English and you're only looking to improve, instead of learning from the ground-up, which makes it much much much easier to actually pick up more of the language.
Humans are freakishly good at learning languages. That's like, our whole thing. It's super easy to actually learn the language once you get the ball rolling by only engaging in english