Have you ever tried in a focused way to 'hack' a standardized test? The best thing about any standardized test is that the concepts are just that, standardized.
Start with a used review book that covers concepts and corresponding strategies in significant detail, take some practice tests after going through each section and then do some focused learning (like vocab stems) based on areas you're still struggling with and repeat with more practice tests.
If you struggle with self-paced learning or this process isn't working, there are other pricey options out there. However, as long as you are not scoring super super low, you'll probably be ok. Good luck!
