Well, when I moved to Canada, I spoke little to no English. I made lots of English friends while I was there, and I was encouraged to associate words with pictures (a dog with a picture. Food with a picture) and my friends and teachers were really encouraging and supportive while I learned English.
Japanese anime is a good start. For me, watching lots of English TV shows with Japanese subtitles. Eventually, I challenged myself by taking away the subtitles and seeing how much I could understand.
Really, it's just a lot of practice. But since you probably won't be going to Tokyo anytime soon, I'd recommend taking any class you can at school. Also, start small. Memorize tiny things like cat, cute, stuff like that. Don't use google translate either. I'd recommend downloading the app (idk what it's called but it has a green owl?) and learning from there. And watch a lot of videos on Youtube to learn more Japanese.
And don't just watch anime. Watch Japanese movies, TV shows, dramas, documents, anything you can get your hands on. Challenge yourself by taking the English subtitles away, and trying to see how much you can understand. Read a lot of Japanese books with pictures (I had to read a lot of childish English books with drawings when I was learning like Dr. Suess, and Robert Munchkin) you can only get better from there.
私はあなたにすべての幸運を祈ります！(I wish you all the best of luck!)
