I'm not sure I'd be able to offer you an objectively "best" advice, but here's what I did to score well:
I took a lot of practice tests. The first few scores I had were terrible by my standards, but I still continued taking them. Sometimes they were a little fun. Eventually I got to the point where taking a practice test was second nature to me. That's when I started doing extremely well.
I read a lot of challenging books. Some of those books (like Gravity's Rainbow for instance), seemed to be written for the purpose of confusing me, but I sucked it up and tried to comprehend them anyway. Aside from prepping me for the SAT it made me learn valuable things, like how there are people out there who enjoy eating **** as a sex act, and valuable skills such as reading comprehension, sitting-down-for-hours-at-a-time, and acquiring knowledge.
I also lurked this forum. Sometimes for hours on end. I read silverturtle's and xiggi's guide. They were a bit boring at first, but as I became attuned, it turned fun.
>How to do well in the Math section
In your case, I would start by going through the SAT Questions of the Day (which are free), and solving every math problem you find while looking at the solution. Even if you get the answer right the first try, look at the solution. You'll probably learn something.
Go through every test in the Blue Book (it's CC's nickname for the Official SAT Study Guide), and look at your wrong/right answers. Figure out why you did how you did on each of them. It'll appear grueling at first, but you'll have to suck it up and keep at it.
I wish you well on your endeavors. I think you'll definitely know the meaning of "hard work" if you follow my advice.