If you haven't been taught it already, PQE or PIE strucuture is the key to a top english mark. It consists of a Point, Quote/Illustration and an Explaination. The point is what you want to say in a given paragraph. The quote is the "meat" of your answer or what evidence is there to support your point off your reference, The explaination is generally encouraged to be the longest of the three stages as you explain how your point relates to your evidence. I also personally use it to segway into my next paragraph to give the writing a more natural sound.
Futhermore (use this word often by the way along with it's synonyms.You will practically have it available in each point you make), have an introduction and conclusion to your writing. I like to think of an answer as a bit of a PIE-ception, where the Introduction is the point of your answer; the Illustration are the paragraphs that fill up your answer and your Conclusion being the explaination, that explains the paragraphs in a much larger and more comprehensable context.
I haven't mentioned quotes and memorisation as I feel this should be somewhat learnt from simple class attedance. I would reccommend not focusing all your efforts on learning the quote word by word as this rarely grants extra marks. I prefer to learn a few words so I can assemble them into an illustation. For example, long paragraphs can be condensed into adjectives and nouns to be contextualised with your own words. Such as "George is described as having a face that is 'quick'". I only had to remember a single characteristic of George rather than a direct quote from the book (Of Mice and Men). With exponentially less study, we have netted most of the marks.
English is too often compared to subjects such as History and Religion that rely heavily on study and memory. Although these are important in the Junior Cert and are still applicable to English, I would recommend focusing on displaying fluency and insightfulness in your answers. Focus on understanding, rather than learning, subject material if you can and simply put this into words using traditional Point Quote Explain.
Even though PQE should be used for most answers; other formats would demand different stuctures and tones. These should be practiced and understood so writing such answers can feel as natural as PQE.
Oh, and watch out for timing. As you can tell by this answer, I struggle with writing too much on certain questions. I would unironically recommend bringing a calculator into the exam just to tell you how much time to spend on a question.
Hope this helps!