One problem for students is that different teachers, books and websites teach different techniques. Students get confused.
My advice is to stop looking for the magic technique; it doesn't exist. There is no best book or website, and there are many different ways to write a good essay.
You just need one way, one technique that you like.
If you look at my lessons, you will see that I have "my technique" for each part of the exam (feel free to use my techniques if you like them). For example, I always write introductions in the same way, and I always start paragraphs with a topic sentence.
Because of the time limit in the exam, you NEED to know what you're going to do. You need to practise ONE way of working. Don't get confused by having too many options.