What ielts wants you to do in writing test, is the same as the speaking test. You have to explain your stance and why you are saying what are clearly. It’s that simple.
While doing this remember to use simple compound and complex sentences. The first paragraph I wrote, has all three sentence types.
Remember to punctuate well and use correct spellings.
Use good connectors such as firstly secondly furthermore moreover but don’t overuse it.
Most important write simple English but but be very clear on what you want to say. Remember that examiners are reading many essays, so they will not attempt to read again if they don’t understand or you aren’t clear.
Hope this is clear. Reach out if you need more help