Engaging with native material really is the best way to improve. A few months ago I read Magic Knight Rayearth, learned the word 蘇る, thought to myself "when is this going to be useful," and then lo and behold this exact word is used in a recent ad for the Ocarina of Time remake. Getting through my first manga was a struggle. I needed to reach for the dictionary constantly, and even as I try to read more complex stuff, I continue to struggle but eventually it does compound and it gets easier. Like they say, no pain, no gain.