Memorize the 101 most common GRE words
Use free GRE prep materials https://www.ets.org/gre/revised_general/prepare/?WT.ac=gre_prepare_170731
Use one of the Kaplan GRE prep books (I found one laying in the donation bin of my building, and used one that a friend had prior to me) its also only 20ish bucks on amazon.. https://www.amazon.com/GRE-Prep-Plus-2020-Strategies/dp/1506248926
One of the skills that I thought was good was the reverse outline method for passages
Understand the format of the question. Some can be weird question formats, so get used to it. ETS has practice test online, do those.
Google other GRE tips. I think in general, a lot of things can be helpful. I think the combination of the ETS practice questions with the 101 most common words list was the right mix for me.