
Anthony C. answered 03/30/20
Algebra, Latin, Reading
Hi, English Grammar questioner! This is Anthony C. with an answer to your question.
I think firstly you have to consider whether you have asked the right question: is it feasible ("achievable") for you to rise from a C to an A during this semester? Maybe the answer is "yes." Maybe it is "no."
Let's consider the "yes."
Perhaps it is possible for you to achieve an A this semester. However, maybe--I cannot see your gradebook, so I cannot know for certain--maybe the only way for you to achieve an A this semester is for you to make near-perfect grades in your Language Arts class from here on out. If English grammar is a difficult subject for you, going from C grades to A+ grades will not be a quick transition for you.
Let's ask instead, "How can I steadily improve my grades in grammar?" Or, perhaps we could even ask, "How can I build confidence in grammar?"
There are a lot of "ways" to achieve this--tutoring is one helpful way. But I sincerely believe the best way to strengthen your grammar skills is to decide to develop a love for reading and writing. Mastering grammar is about learning to identify patterns in sentence structure. The most effective way to gain this skill is going to be to read more often, to read more carefully, and to try to imitate the patterns you see in your own writing.
Lastly, we know that for school it is often not enough merely to know how to do something--you have to also know the "why"--and the labels we call things by. A math genius may perform poorly in math class if he never shows is work. A brilliant writer may fail his Language Arts quiz if he does not know what a prepositional phrase is (even if he uses them well).
For things such as that--the moments when you need to begin labelling grammar constructions--it may be necessary to purchase a manual for English writing skills--or to hire a tutor.
I will suggest some manuals in the rest of this thread.

Anthony C.
Here is a link to some reference books and coaching books on grammar: https://booksrun.com/blog/7-best-writing-reference-books-and-grammar-guides/ I would strongly recommend Strunk and White's The Elements of Style and the Penguin Guide to Punctuation. But these are reference books: materials to use throughout your coursework as you have questions. They will probably not help for a weekend cram session. Take care!03/30/20