ANY ADVICE????

I’m currently a senior and I have taken the SAT twice, I have gotten 1550 both times. I have two more chances to take it, november 7th and the one in december. I am really worried that I wont be able to get my scores up. Unfortunately i can not afford a tutor at this time. My goal is to get above an 1800, a 1900 would be much more desirable but at least an 1800 would be amazing.
Any tips or other information would be so helpful and greatly appreciated! Thank You.

What is the breakdown? I think Math is the easier to improve.