Retake strategy advice

Hi all!

This is my first post, and it comes after actually taking the gmat for the first time today and scoring 600 (37Q 35V). I've done a minimum amount of work for it (<8 hours in total, not a single full length test, just did a few questions from each section in the OG).

The problem is I want to improve to somewhere in the 680 region and I have 4 weeks to do that, as I have to send my application by the 2nd of Nov. I'm willing to work everyday, but I really don't know where to start, so any advice on a strategy would be highly appreciated.

Also, was wondering if the 800score prep package is any good... I'm not able to afford the 600$+ price tags on any of the online courses I've found. Any ideas in this area?

Basically any advice would be useful!

Thanks for your help and congratulation on the great community you have here!