How do I include critical viewpoints into my essay response?

Firstly, do you need to include critical viewpoints? Is the question inviting you to read a text closely, or engage in a broader analysis of the text as a whole. If the question falls along the lines of the first description, then I wouldn't include critics. However, in broader questions, examiners like you to use critics to support your argument. You should highlight the key terms of the question: what is the question asking you to do, and what critical viewpoints would be best to support my overall argument? When using a critic, it has to be relevant to the question, but most importantly to enhance your main argument. Critical responses shouldn't be for window-dressing a weak essay response.