Well you'll have to find a learning method that works for you, that's how any language goes. Kanji is something you'll work on for a long time alongside whatever else you're learning. You'll need to decide on methods to study grammar and vocab. Also find ways to practice all four language skills: reading, writing, listening and speaking.
I would personally suggest either finding a class or a textbook that you are comfortable with and set a schedule for yourself, if you're serious about it. If you don't want to invest too much I'm sure you can find free beginner grammar lessons online somewhere, but most free material won't get you past a beginner or low-intermediate level.
Lately I've just been using the JLPT as a guide in a way. You could pick out the easiest level N5 and just say that you want to feel confident in the skills you'd need to pass the N5 in a year or 6 months or whatever. Then start the next level.
It's hard for me to tell you how to begin studying on your own, I took college courses for Japanese and I personally believe that's the best option. Easy access to a community, support, and a framework to structure your study around. And once you're done you know HOW to study. If you really commit yourself to using communities like italki and lang-8 you might be able to make it work though. There are great resources online but I've always thought of them as supplemental.