Personally here are the ways that work for me:
Pick related materials that click with you, there isn't a point choosing a related that you're not willing to read/watch and study and it'll improve your life by a mile
My personal favourite is reading high B6 essays or exemplars and use their vocabulary and their techniques and especially their form/structure, a lot of teachers do not teach form well or emphasize it enough so students with poor teachers tend to have weak form.
Take your time to write it and to edit it as you go. I know many students who rush an essay and then try to fix it up as they go and having to go through too many drafts just to get it right.
Planning and rough scaffolding helps me alot before I write. I like to list my concepts and the quotes before I write so there's less thinking as I type. (This usually means I spend a few hours just to get the planning right)
Having an English study group is also useful since you can read your peer's work and vice versa - this gives you the opportunity to see different perspectives and tells you the kind of standard your cohort may be at. (Ps. This works best if your study group has students in the A range and with people who are willing to roast your essays and give constructive feedback)
Not sure about the 2019 syllabus but for the 2018 students, it's good to do an AOS paper once a week or fortnight so you don't get rusty and can familiarize yourself with type of questions and the Discovery rubric.
Personally, English lessons close to exam dates are pretty boring and useless unless they're teaching you actual content or offering to read your drafts, I like to read short stories and Band 6 creative pieces so I can see what it takes to do well.
Otherwise just work on your essay, perfect it and then give it to every teacher you find.