When I took the GRE, I relied more on the word roots and affixes that I knew rather than the specific words I studied. I don't think I got more than two words that I actually studied, but I was able to figure out the meanings of many of the hard ones by taking them apart. That's also how I succeed at FreeRice
My preferred method was virtual flash cards, I think I googled "gre word roots virtual flashcards" or something like that. Sorry I can't find the site I used anymore.