Totally sort of on topic, but the key to the SAT is practice - repeated (timed) practice tests, reviewing and working through questions you missed, and then more practice tests is the best way to get a decent score. You can usually access these online now, but a normal book that reviews typical concepts on the test is good to have in order to review. 4-6 weeks of consistent practice would get her in good shape.
Also - not sure how many schools still accept the ACT, but I did much better on that than the SAT for some reason. May be worth looking at where she is applying and if they accept that test as well.
I did the exact opposite - I did spectacularly well on the ACT but only very good on the SAT. The SAT has changed over the years, though. Now they are giving points for "disadvantagement" (I know, it's not a word.) And there's a writing component. When I took it there were only three main tests.
Once upon a time the tests were to show where you were at a given point, academically. One did not "prep" at all for the tests - you either knew the material or you did not. That, obviously, has changed since parents started really pushing their kids to perform well on tests. There are now masses of high school kids being groomed on how to take the test. While not getting the other part of what education really is supposed to be. Too bad, really, but I doubt it will change now.
If it were me, and if it were the Daughter who was of an age to be considering higher ed, I'd send her to a smaller school that relied waaaay less on test scores and more on personal interviews, personal recommendations, and a portfolio of achievements. There has been a movement in some of the more progressive schools to not consider the standardized testing very highly in the admissions process. Which is a great step, in my mind. It's not all that useful as a barometer of how well someone's going to do once they hit higher ed, which is usually a vastly different environment from high school.
Whichever school a kid applies to, I would urge serious research to see if they are a good "fit" for the campus culture - you don't want a fine-arts kid going to an "engineering" school, even though they offer fine-arts degrees. And look at their placement office - both the record of placements after graduation and the services the school provides. Some are pretty much "don't let the door hit you in the backside as you're leaving us" types, who do almost nothing to help their alums find that critical first employment.