Techniques to improve expression of arguments HELP!

[NoHeart]

I have an English SAC on 'Twelve Angry Men' next Wednesday, I have been writing a few practice essays but I find it difficult to express what my arguments are well. Unfortunately because my teacher gave us a practice sac to do recently she won't be able to give me feedback on essays I write at home for a few days. Does anyone know any good techniques to learn how to have clear expression in my body paragraphs? Such as examples of good paragraphs with clearly stated arguments or exercises to do that will help clear my mind when writing. I only have the text that I can analyse for now so any help will be greatly appreciated!!