I have little vocabulary, and a little grammar under my belt. I wanted to learn kanji first, because I was overwhelmed with all the kanji i didn't know. My main concern is learning to read/write first.
Do you already understand what you're reading, provided you take the time to check new words in a dictionary?
If you do, then practice reading, make lists of new vocabulary and sentence constructions, practice writing the new vocabulary you learned when reading and repeat the process with new material.
If you don't, well you might want to stick to your school books a little longer, until you know enough sentence structures, so that you can pick the stuff you want to read by yourself.
Cramming lists of kanjis isn't really useful. You'd better learn new kanjis through words that are actually useful. The best way to do it is through reading stuff that catches your interest, indeed, but it needs basics in grammar. There isn't really something that you have to learn first, vocabulary and grammar go by two, and kanjis go together with the new vocabulary. It's just that you'll still be learning new vocabulary when your grammar has already reached a good level and even after.