Make sure you’ve used the right words to explain yourself. There are several different things to consider for vocabulary:
Vocabulary for audience
Have you used clear, simple terminology so that most people will understand the text? If your intended audience is a fairly small group, have you used the vocabulary which will give them the most information? For example, if you were discussing grammar, most people would be happy with the term conjunction, but a group of linguists would want to know what kind of conjunction it was: Co-ordinating? Correlative? Subordinate?
Vocabulary for subject
Have you used the vocabulary generally used to discuss your subject? If you’ve written a short history of the theater, have you actually used the word theater? Actor? Stage? If not, do you have a good reason for not doing so?