1. Keep it simple. 保持文章的简洁。
Simple done accurately is better than complicated done inaccurately.
In other words, it's better to keep things simple and do it well, rather than over-complicate everything and do it badly. So in taking your English exams, you want to show off your English, but you want to show off your accurate English, not all this English that you don't know or haven't learnt yet.
2. Prepare key phrases. 准备重要的短语。
In order to avoid making mistakes in your writing, it's a really, really good idea to have a collection of set phrases and keywords that you can use in that exam.
You don't want to rehearse what you're going to write, but you do want to have a nice selection of things that you could possibly say if the time arises. Especially on the IELTS exam, and I know a lot of you are studying for this, but this really goes for any academic writing exam, you want to have linking words and key phrases prepared.
Go and do research, and prepare yourself.
3. Do not use contractions. 不要使用缩写。
Use: cannot, do not, it is, they are, they are not, it is not, I am, should not, etc.
4. Reduce your word count. 减少字数。
Use as few words as possible. Word count down and English level up.
Avoid "very", "so", "a lot", "really" and replace them with a strong word. Instead of saying "I am really happy", say "I am elated." Instead of saying "so scared", say "terrified".
Avoid "there is" and "there are" which add extra words to sentences. Instead of saying "there are many problems that we may encounter", say "we may encounter many problems".
5. Read the right materials/documents. 阅读正确的写作范文。
Read the right pieces of writing.
You need to go online or go to libraries, and read articles, read reports, read essays, read reviews. Do everything you can to familiarize yourself with all the styles of writing.
6. Check your own work. 自己检查自己的写作。
In writing exams, you want perfection.
7. Write and get your work checed. 付费找人批改你的写作。
Get a proper teacher and pay them to help you. Why would a random stranger on the Internet want to help you with your writing?