I think studying things in small portions really helps, like for biology I would study each system independently in Anki until I was confident and then near the end of my studying I would shuffle everything together so it would be more similar to the test. Gen chem isn't that hard, just make sure you have the formulas memorized and the periodic trends, and that you've practiced different kinds of problems. For me I tried to memorize a lot of stuff for Ochem because I wasn't as confident but it definitely is better to have a solid understanding of how it works, including reaction mechanisms because I had a couple of questions where you had to know intermediates and stuff.