Oh English was my strong suit! I really found that for literature, a 'fact file' of some sorts for all the quotes to remember for the character/poem (usually like 6-8 for characters, a lot of quotes crossed over) with their explanations AS IN DEPTH AS POSSIBLE helped me- obviously not for everyone. Answer as many essay questions as possible and try to squeeze as much as you can out of a quote, look at it from any and all angles. Learn key terminology like the sibilance reflects this, and link texts back to the context/time the text was written. Try get your teacher/s to mark what you write. The best advice I can give you for language is do past papers like your life depends on it AND GET THEM MARKED!! I also liked past paper walk throughs on YouTube. I had two past papers (one for each paper) that I annotated on how to get the highest marks for that question. The thing about language is it is no longer about the explanations but rather the coverage. You have just got to get as many quotes as you can possibly get in with one line of explanation. For top marks, use subject terminology on ONE OR TWO QUOTES AT MOST.
Good luck, you got this!
Oh, and a small edit here, 6s are still an awesome grade.