After the first month or so, I find extensive reading (with graded readers) to be by far the fastest way to pick up and cement vocabulary gains.
Listening (to radio or podcasts) is harder until you building a larger vocabulary, so I gradually add it to my reading habit as I improve.
Perhaps you now see in what specific ways the practices you mentioned might help you. Be creative with them make it fun and enjoyable
P.S. your associative memory doesn't discriminate, try not to mix your learning with things you don't want to pop in your mind later e.g. learning another languager, baby screaming from the other room, stress, etc.
Pairing opposites in this fashion amounts to reducing the recall effort (At least for me). It is somewhat like getting recall of two words for the effort of one.
I also tried to identify common recited listings of words such as" "Who, What, When, Where, Why and How" and then learn them by rote in the second language.
I’ve created vocabulary books with the 2000 most frequently used vocabularies for 40 languages (so far). You can find that here: https://www.pinhok.com/
Those are real translations, not Google Translate, and all cross checked and proofread.
Came up with this for myself when learning Cantonese. Before that I found HSK (Chinese standard test) very useful which kind of follows a similar approach.
It’s not for everyone, but people who like 80/20, etc. might find this quite useful
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).
For example you can see the connection between Spanish 'mano' ("hand") and English 'manufacture', 'manipulate', etc.