Expository writing fails its mission if it diverts the reader’s attention to itself and away from the topic; the process of writing should be transparent to the reader. In particular, the prose itself should direct the flow of the narrative without requiring you to play tour guide by commenting on it. Do not say, "Now that I have discussed the three theories of emotion, we can turn to the empirical work on each of them. I will begin with the psychoanalytic account of affect..." Instead, move directly from your discussion of the theories into the literature review with a simple transition sentence such as, "Each of these three theories has been tested empirically. Thus, the psychoanalytic account of affect has received support in studies that..."
Do not say, "Now that we have seen the results for negative affect, we are in a position to examine men’s and women’s emotional expression in the realm of positive affect. The relevant data are presented in Table 2..." Instead use a transition sentence that simultaneously summarizes and moves the story along: "Men may thus be more expressive than women in the domain of negative emotion, but are they also more expressive in the domain of positive emotion? Table 2 shows that they are not..." Any other guideposts needed can be supplied by using informative headings and by following the advice on repetition and parallel construction given in the next section.
If you feel the need to make metacomments to keep the reader on the narrative path, then your plot line is probably already too cluttered, the writing insufficiently linear. Metacomments will only oppress the prose further. Instead, copy edit. Omit needless words; don’t add them!
Use Repetition and Parallel Construction
Inexperienced writers often substitute synonyms for recurring words and vary their sentence structure in the mistaken belief that this is more creative, stylish, or interesting. Instead of using repetition and parallel construction, as in "Men may be more expressive than women in the domain of negative emotion, but they are not more expressive in the domain of positive emotion," they attempt to be more creative: "Men may be more expressive than women in the domain of negative emotion, but it is not true that they are more willing and able than the opposite sex to display the more cheerful affects."
Such creativity is hardly more interesting, but it is certainly more confusing. In scientific communication, it can be deadly. When an author uses different words to refer to the same concept in a technical article—where accuracy is paramount—readers will justifiably wonder if different meanings are implied.