How can I improve my math score?

I got a perfect on the math portion of the PSAT, but the first time I took the SAT I only got a 650. I was a little surprised since I’m generally good at math, but I just figured I had a bad day and that I was a little rusty with some of the material since I hadn’t learned it in like 2-3 years. I studied a fair amount to take it again and averaged around a 760ish when I took practice tests, but when I took it again I still got a 650. When I was taking the SAT for the second time I felt like I did a lot better on the math but I ended up getting the same score.

Can anyone suggest what to do to improve my score? I’ve gotten all As in math (up through AP BC calc) and I tried to study algebra and geometry before taking it to brush up on those skills, but it still didn’t really help. It just seems weird to me since I do well on practice tests and did really well on the PSATs. Any advice would help!