I had a score increase like this earlier in the year, but I had 2 months in between (definitely didn’t study the entire time lol).
This is what I did for English (not an expert though this might’ve just worked for me):
-Take a few practice tests
-Identify weak areas
-Use SAT question bank for weak areas (working from easy to difficult)
-Watched YouTube videos for questions that I struggled with, to help develop a strategy
For math:
-CollegePanda
-Watched videos about Desmos
-Tried challenging math problems on the SAT question bank
Math is my stronger subject so it’s hard for me to say exactly why I improved, I think my math class helped me
When taking the English section, I started with the back half (like the transitions and then the questions with the bulleted lists), then went to the beginning, and saved inference+data questions for last (these were my weak points). Try this on a practice test before doing it on the real exam.
I did A LOT of English questions from the SAT bank, pretty much finished all of the difficult questions for my weak areas. Though I got a 750 so there’s still a lot of room for improvement.
https://satsuitequestionbank.collegeboard.org/digital/search