Failed cosmetology state board twice — what study method actually works?

I'm honestly embarrassed to even post this, but I failed my state board practical AND written for the second time last month and I'm at my wits' end. I graduated from cosmetology school back in February, I thought I had a decent handle on things, but the written section keeps tripping me up — especially sanitation/disinfection procedures and the chemical services questions. My school gave us some review sheets but they're pretty thin and I don't think they're covering everything that shows up on the actual exam.

I've been looking into using a COSMETOLOGY BEAUTY practice test to drill the written portion more systematically before my third attempt in July. Has anyone actually improved their score significantly by doing timed practice tests? I've also seen a few study guide options online — worth buying one or is free material enough? I really need to pass this next time because my job offer at a salon is contingent on my license. Any advice from people who've been through this would mean a lot.

For context I scored a 68 on my last written (need a 75 to pass in my state) so I'm close but clearly missing something in how I'm preparing.