I am so worried about the GRE exam! I have not any experience about it, but need to take it in order to do my PhD in the USA. So far I prepared a vocabulary notebook and wrote the definitions of 3500 words. Now, I am thinking of how to memorize those words in a short time. Moreover, I need to study for the Math and analytical writing sections.
I highly recommend Magoosh. I used their vocabulary app while I was walking around campus for a couple months and by the time the exam came I was thoroughly prepared. They also have a pay-for-service learning course which is good to review the material you've forgotten since high school. I am a fairly math oriented person going into the life sciences so I did not do too much of the math portion of Magoosh but the writing section was fairly useful and the english section was great. Knock 'em Dead!
For the vocab you could download this flashcard deck https://ankiweb.net/shared/info/2430987595 and the software anki. It's a spaced repetition software with a little bit of a learning curve, but once you get it down it is highly effective. Or you could search memrise for a few gre decks.
I just bought a GRE workbook. I have yet to crack it open, so i cant review it. But it has a lot of quanatative questions that mimic the GRE. So a work book and some flashcard software would be your best bet.