One of the first things I learnt, a long time ago, when I started university, was that when writing an academic essay, structure is almost as important as content.
Structure = HOW you write your essay
Content = WHAT you write about
Furthermore, if you know and can easily create an effective essay structure then you do not have to think about it when you start writing. This means you have more time to think about your content.
Structure is also very important because it helps the reader to more easily understand your ideas and arguments in your essay. Readers (and examiners) in my culture expect an essay to have a set structure. So, if you're trying for at least a 6 - 7 IELTS score or just want to improve your essay writing, the first thing you need to do, is have good structure.
Here are the first FIVE STRUCTURAL tips for writing a good essay.
ALWAYS write FOUR PARAGRAPHS. Always.
Your first paragraph is your INTRODUCTION
Your last paragraph is your CONCLUSION
Your 2nd and 3rd paragraphs are the BODY of your essay
ALWAYS start your 2nd and 3rd paragraphs with a TOPIC SENTENCE
Writing a good essay is like building a house. For the house to be strong you must have good solid foundations. The essay structure is the foundation of your essay. Do it right.