1. Frame the sentence so that it can have but one possible meaning.

Wrong: He owned several dogs and was greatly troubled with the mange.
Right: He owned several dogs and was greatly troubled because they had the mange.
Right: He was greatly troubled because several of his dogs had the mange.

2. See that the antecedent of every pronoun is clear and explicit.

Wrong: The dog was bitten on the front foot which has since died.
Right: The dog, which has since died, was bitten on the front foot.
Right: The dog was bitten on the front foot and has since died.

3. See that the word to which each modifier refers is unmistakable.

a. Place every modifying element as near as possible to the word which it modifies.

Wrong: He was sitting in a chair reading a book made in the mission style.
Right: He was sitting in a chair made in the mission style and was reading a book.
Right: He was sitting reading a book in a chair made in the mission style.
Wrong: The table had been inlaid by his father, containing over fifteen hundred pieces.
Right: The table, containing over fifteen hundred pieces, had been inlaid by his father.
Right: The table contained over fifteen hundred pieces and had been inlaid by his father.

b. Avoid the "squinting construction." By this term is meant the placing of a clause so that it is impossible to tell whether it refers to the preceding or succeeding part of the sentence.

Wrong: It would be hard to explain, if you were to ask me, what the trouble was.
Right: If you were to ask me what the trouble was, it would be hard to explain.