>>24590973>>24589309>>24590539In case you want to know.
Duo is good for more Roman languages, Japanese and other Oriental languages don't do that well with how Duo is structed to teach. It's good to use up to a certain point, but once you've gotten the hang of katakana/hiragana, go a little further to get a hang of the basic grammar and some kanij, then read a grammar guide like tae kim's to get a little more in depth, and from there dump duo and start trying to immerse as much as you can. That's the best I can give you as someone who's started making good progress recently, that and DON'T slack on your listening reps and your speaking reps if you've got someone to talk to, the guys are great for this.
