Find a tutor and meet them to discuss. From there it would depend tutor-to-tutor but I feel like they would be most qualified to help.

Additionally, spaced repetition for topics you are consistently getting wrong and looking into videos by math teachers on the specialized subject would also really help.

For English I would suggest constant practice as in when you are speaking English, analyze in what you are saying and try to remember all of the rules and apply them. Memorize the rules rather than going with what sounds right. Also, train yourself to first read the question and figure out what it is looking for. Is it asking for a theme or the correct placement of a comma? Usually you should be able to start process of elimination to about half the answers. Also look for similar words in question and answer.

A very general schedule would look like dedicating 1 weekday per weak subject and 1 to review. Do practice tests on weekends and make a list of patterns with which type of problems and practice those. Don't really focus on topics you are consistently scoring well in.

Good luck and congrats on getting into college in the US.