How can I boost my SAT score by 300 points in a 5 month period?

hi, before taking the December 3rd SAT exam, I only practiced about 20 days through Khan academy because I was quite busy with sports.
Is there any tips and/or strategies to boost my SAT score in the next 5 months? I want to register for the June 3rd SAT.
I got a 1200. I was 100 points away from my initial goal of 1300 (I knew I could take it twice because of fee waivers).
I want to score in the 1500-1600 area, but I don’t have the money for a tutor or expensive online prep.
I also have the SAT books package provided by my school.
Strategies?

I suggest dedicating at least a half hour to 1 hour a day to studying for the SAT. Hopefully you have the breakdown of your score on the math section and the English portion, so you can see which you need to focus more time on. I highly recommend you look at online sample SAT questions – most websites give you free access, with answers and explanations. Don’t spend so much time studying at once that you aren’t retaining the information, instead study in blocks and take breaks in between. Try speaking to your GC at school, because sometimes they can be a good judge of specific ways each individual should study (because studying approaches really vary from person to person).

Work on your lowest section. It’s easier to raise your score faster by improving your lowest section.

5 months is plenty of time.

Khan Academy is a pretty good place to start, but if you want to score 1500-1600, Khan Academy won’t be enough.

I recommend Erica Meltzer’s Reading and Writing Books for the Reading/Writing section.

For Math, Dr. Chung’s SAT Math book is pretty advanced and good if you want to score 700-800 in the math section.

As for practice tests, I recommend PR books and Ivy Global.

These books altogether will probably cost you around $100 on Amazon, maybe a bit more. However, it is still cheaper than a tutor or an online program.

Perhaps I can comment more if you specify where you are having trouble on the test and/or your score breakdown.
What books does your school provide?

I got a 600 on both sections

I would caution you on the Dr. Chung book. My DD tried to use the version for the SAT Math Level 2 subject test and found it way too complicated. She ultimately scored an 800 on it and a 36 on the math section of the ACT but she could not get through the Dr. Chung book. I would Reccomended you look to see what resources your local library has for you to use. I do agree with the Erica Meitner book reccomendation.

Just keep redoing the questions you get wrong. 90 minutes a day should be enough. Best of luck.