WaniKani teaches you the Kanji. That’s it. Well it also teaches you some vocabulary, but that is primarily to reinforce the learning of the Kanji.
What you will also need:
- Reading practice
- Listening practice
- Writing practice
- Speaking practice
Genki is a popular choice for learning grammar and some vocabulary. It didn’t click with me personally, but it’s definitely worth a try. I like Tae Kim, but many people are critical of his approach. Most likely you will need to compare several choices and see what works for you.
For vocabulary there are obviously some core words that everybody should know, which can be drilled in with an Anki deck or whatever.
But more importantly I would encourage you to ask yourself, why are you learning Japanese? What is it that you want to read, or watch, or who is it that you want to talk to? Focus on the vocabulary that is specific to that goal. Same with reading - Sure NHK Easy News is great at the start, but I would try as early as possible to read whatever it is that you’re interested in, even if it’s at a glacial pace.
With talking, obviously the best thing is to just talk to a Japanese person. Most people don’t have a Japanese person to talk to, so online services like iTalki are a good idea.