Read the question, then read it again. Then answer the question. Then read the question again to see if you answered the question.
Use primary sources. If your essay is on Luther, read some Luther. If its on Calvin, read some Calvin. And show that you have read them by citing them and engaging with them. Use secondary literature as a guide to where to begin to read your primary sources.
When dealing with 2 (or more) people think about the order in which you deal with them. It is usually a good idea to deal with them in temporal order with the earliest first.
Some essays are padded with facts and details not really relevant to answering the question. While demonstrating extra knowledge can seem like a good idea, if it is not directly relevant to the question then it doesn’t earn you any points.
It is a good approach to describe someone’s ethics or theology and then evaluate it. If you mix the two then sometimes it is difficult to tell where they end and you start.
Use grammar check on your essay before you hand it in.
At the first use of someone’s name use their full name not just the surname.
Do not use etc., e.g., or i.e. in academic writing.