I have difficulty in answering accurately SAT math questions when I am under time pressure. I end up making careless mistakes. Is there anything you can suggest to me of how I can practice of not making these kinds of mistakes under pressure.

The only way I know to get better at dealing with pressure is to work under pressure often enough that it doesn’t feel like pressure. Do your best to make every practice test you take feel like the real thing, and then hopefully when it IS the real thing it won’t be so overwhelming.