Hey, I am also trying to improve my English vocab and think that reading books in English is the best way. I don’t read it 20 times, it should be very boring. I even can’t imagine! I read the page once and create lingqs, try to understand the contex of the text then start the audio and let the narrator read it for me. It’s also good for listening practise. I mostly choose the difficult texts and try to understand everything. (While reading in English or German) Because I feel confident in English or German and have no problem with grammer etc. I think that I have to enlarge my vocab and increase my eloquence.
I spent some time with Spanish which is a new language to me. I didn’t force myself to understand every single thing in the text instead I tried to get used to the logic of the language and the way of thinking of the Spanish speakers. Because I think learning language is learning a new way of thinking. If I start to learn a new language I don’t force myself, try to get used to the logic and understand how they think.
Sorry for the rant! This is how I do.