I did not get 7 in any of my attempts. In the latest attempt, i got 6.5, but when i applied for EOR, it got changed to 7. I may not be the best person to help you out. But, I guess you need to use proper linking words, paragraphs should be coherent like from start to end. Always don't go off topic. Make sure, you don't repeat the words in the question, Instead use synonyms and also explain both sides of the argument and pick one side eventually. Always write 5 paragraphs, like introduction, against, for, for and conclusion. Use the same style for causes, examples and effects question as well. Lot of youtube videos available. Make sure, you plan your essay for 5 min, like what can be my for or against points with an example each. write the essay in 30 min and spend the last 5 min to double check for any grammar or spellings. All the best.
https://www.quora.com/How-can-I-score-a-7-in-the-IELTS-writing-part