I have found wanikani to be amazingly helpful. I took a class years ago and tried to keep progressing in Japanese but had a terrible time with learning new kanji. I knew less than 100 when I started wanikani last October and I have about 750 at guru+ right now. I’m not claiming this to be fast, but relative to the casual effort I’ve made, I have seen tremendous results. Japanese used to be more of a novelty hobby for me than anything, but now I feel confident enough that I use my phone, computers and many websites entirely in Japanese. I’ve gotten some raised eyebrows at work when coworkers noticed that my PC language is set to Japanese.
Immersion has helped me a lot. If I just do rote reviews over and over, I don’t retain words very well. But when I start seeing them in news, Japanese language groups or other media, it really helps to reinforce my ability to recall them. I also avoid the English mnemonics on wanikani and try to relate kanji together mentally by reading and/or meaning when possible. For instance, 定 and 提 which share the 音読み てい
Or 低 and 底 which also have てい as an 音読み and what seems to me to be a similar meaning. Those are two examples. This is probably also a flawed approach but I try to use the language to learn the language where possible. I’ll ask my phone 「何何の意味」 where 何何 is some word that I don’t know, and see if I can understand the definition.
Of course there are also sources like NHK easy news, and I play games in Japanese when I can. I am playing the new Zelda on the switch entirely in Japanese.
These have all helped me a lot to immerse myself and I do feel like the language is becoming far more natural for me, particularly in that I don’t always have to mentally translate my English thoughts to Japanese words anymore. I also disable furigani on sites and etc when I can; if I really don’t understand a character and need to, I look it up on Jisho by radical, but if the furigana was there I will naturally want to read the kana as it is easier than kanji, since I’ve been able to read kana for over a decade. So I try to get rid of the crutch.
I’m not claiming that any of these are the right approaches, they’ve just been working for me and it is gratifying to see the tremendous progress that I have made without overtaxing my time, interest and capacity to learn the language.