A couple years back when I was still fairly new to this, I would hear very often that you should read, read, and read some more to really push your Japanese ability further. This is still commonly given advice in Japanese learning circles. I think anyone who's seriously tried to do this has at some point probably faced the frustration of having to look up too many words. Hence what I eventually started to do was pre-learn vocab words contained in things I was interested in, to reduce dictionary look-up burden.