I have lived in Japan for over 4 years. I have taught English in Tokyo, Kyoto, and Osaka. I also studied Japanese in Kyoto, so I can help you a little in Japanese.
I think it's important to connect English with your interests. Grammar books are a useful tool, however learning a language requires continuous and dedicated practice. If you connect English to your personal interests and passions, practicing will come natural and studying will be easier.
がんばりましょう!!