LogFAQs > #950713907

My biggest advice would be to consume native material- read manga, visual novels, watch anime, etc. Easier manga are doable pretty early on. It's not a big deal if you don't understand everything.

If you want to get corrections on your written Japanese there are sites where natives will do that for you and you can correct their English in turn. Lang-8 was really popular with Japanese people but they closed down registration due to security issues or something.

There's also this site https://langcorrect.com but don't know how active it is. It was supposed to be a replacement Lang-8 but not sure if it ever took off.