I think there's no single answer. I usually experiment with different methods and stick for a bit longer with the one showing the best results. But I often get

I think there's no single answer. I usually experiment with different methods and stick for a bit longer with the one showing the best results. But I often get "saturated" and, when I feel I reached a plateau, I start to try new methods (even methods I've already tried and disliked at the first contact). Memorization-based methods like spaced repetition flash cards never worked with me, but I know some people who got wonderful results out of it. I use sporadically the paid version of lingq.com. It has some annoying bugs and the usability isn't great, but I enjoy the method. I try to talk to native speakers whenever I can. That helps to build emotions related to the new language and I feel that those emotional connections usually help to "burn" the new vocabulary into your brain, it doesn't matter whether the emotion is positive or not (that's my experience at least).