Tips for GRE?

Hi! I plan on applying to PhD programs in economics (I don't know if it's relevant, but my focus is on macroeconomics and monetary policy). After seeing the GRE from previous promotions for the universities I'm interested in, I noticed the high requirement for quantitative scores (165+).

For some context, I did a bachelor's in International Relations (had basically no math during my degree) and I'm currently doing a master's in Econ. Still, with a more theoretical approach and just the use of basic math and statistics knowledge applied in Excel and R. So basically I would need a good refresher on most of the content and even study new topics.

With this in mind:

• Do you have any tips or suggestions for studying?
• Is there any course, platform, or GRE guide prep book you would recommend?