Point 20: Staying Specific
Avoid broad claims unnecessary to your particular argument. Faced with the tricky task of opening or closing a paper, some writers will fall back on wide-ranging generalizations: "Throughout history, humans have feared death," they might begin, or "Until modern times, society offered little freedom, especially to women." Some such statements can be defended, and some cannot; either way, they nearly always distract writer and reader from the meat of your argument.
One way to test your claims is to see whether they could work as well in totally different papers. (Note how little the above examples tell you about the overall direction of an argument.) The poet Samuel Taylor Coleridge tells of his boyhood teacher who expressed this notion more colorfully than I:
there was one custom of our master's, which
I cannot pass over in silence, because
I think it imitable and worthy of imitation.
He would often permit our theme exercises,
under some pretext of want of time, to
accumulate, till each lad had four or five
to be looked over. Then placing the whole
number abreast on his desk, he would ask the
writer, whether this or that sentence
might not have found as appropriate a place
under this or that other thesis; and if no
satisfying answer could be returned, and two
faults of the same kind were found in one
exercise, the irrevocable verdict followed,
the exercise was torn up, and another on the
same subject to be produced, in addition to
the tasks of the day.