Remember if you are writing a persuasive response you need to indicate that you can use some rhetorical or persuasive devices. You also need to demonstrate that you can appeal to your audience. You also have to show that you can develop your ideas in a structured argument that is organised in paragraphs. Below are some links to resources explaining some of the common persuasive techniques.
When you are editing your writing, remember to take a few minutes to read over what you have written and check for spelling, punctuation and sentence structure. This becomes very important. You do not need to write more than 500 words.
On this page, you will also find a really simple list of connectives, emotion and tone words, and a few other tips.