So, I took the June 2016 ACT with Writing for the first time and going in, I thought I was going to do fine since I am one of the top writers in my grade. So I mainly wrote about my opinion and sprinkled in how the perspectives related or differed from my perspective. I ended up with a 21! What happened? I think I may have strayed from the topic and wrote the essay more like an argumentative piece as from school. What did you guys get on it? How do you even write the type of essay ACT wants? Are there any examples online of an essay that got a 36?
I was worried about this too when I first took the new ACT writing. I did some research and I discovered that the writing score is completely separate from the composite. Your score of 21 is actually in the 74th percentile. A 36 is highly unlikely to ever reach (I do have one friend who got a 35 though). The 99th percentile starts with a 32. If you are scoring in the 99th percentile for your composite, I would aim for at least a 30 in the writing. However the scoring is very inconsistent in my opinion.
The good news is that the ACT is changing the scoring this September 
It’s the same 4 domains on a scale of 2-12 but instead of converting that to a 1-36 scale, they are just going to average the domains. So the score on your report will be out of 12 like how the old ACT writing was graded. This will make it so much clearer that the writing score is not related to the composite score. It’s naturally lower. People need to think of it as a different score all together. There’s a reason it’s not included in the composite. On the new scale 10-12 will probably be the 99th percentile. That’s how it was for the old ACT writing.
If you want to improve your score you should read the PrepScholar guide to the new ACT writing. I did it exactly the way Alan said to and scored in the 98th percentile (I also thought my essay was terrible).
Hope this helps!
I got a 36 on the writing last December so hopefully I can help! The new writing prompts are leaning heavily towards a DBQ/synthesis style essay (just watered down) so focus on having that degree of organization. Think 5-paragraph essay if you have time, with a very very clear thesis that outlines your main points, and an an opening and concluding paragraph. This makes it easy for the readers (they have a LOT of essays) to understand that you know what you’re doing without having to search for your points.
As for your arguments themselves, let the prompt guide you - usually it’ll imply what you can use for at least two body paragraphs. Even though it’s an opinion essay, work on heavily analyzing/comparing the perspectives they give you and pointing out their flaws (or merits) rather than just writing about your own thoughts. Definitely bring in real-world examples if you can (historical comparisons are great, personal experiences can work well if they’re well-executed.) Mostly just try to show that you have a thorough understanding of the perspectives they’ve given and can form an opinion on them based on sound evidence.
Of course, I’m not an expert on the ACT writing! This is just what worked for me and a few of my friends that have scored well. Good luck!