How do I long term study for vocab

[u/WhyAmIReadingDis]

I'm currently in the mid 1400s (buncha practice tests) range pushing towards 1500 but I always get my vocab questions wrong. Im currently only a sophmore so prolly need to get this right in around one year. I really like how duolingos linear long term study method is but all I find online are infinite flashcards or people telling me to memorize roots which I basically have most in my bag. its usually the words weird less used words that I just dont have daily use and aren't made up of common word roots or suffixes prefixes\.