Raising an SAT score by 700+ points is extremely difficult, even if you did slack off while studying for the first SAT. You’ll need to make sure to buy a plethora of SAT prep books, which I believe can be found on the SAT sticky thread “How I raised my score by 730 points”, or something similar. I also suggest a private tutor, with my personal favorite being PrepScholar: https://www.prepscholar.com/sat/s/. You’ll need to study for at least a solid 10 hours every week. If you follow these and even extend beyond these, then your chances of a 700+ point raise will look less impossible.