Diction - Purity - Propriety - Precision.
Clearness of style should be one of the leading considerations with the
beginner in composition. He must avoid all obscurity and ambiguous
phrases. If he write a sentence or phrase and see that a meaning might be
inferred from it otherwise than intended, he should re-write it in such a
way that there can be no possible doubt. Words, phrases or clauses that
are closely related should be placed as near to each other as possible
that their mutual relation may clearly appear, and no word should be
omitted that is necessary to the complete expression of thought.
Unity is that property of style which keeps all parts of a sentence in
connection with the principal thought and logically subordinate to it. A
sentence may be constructed as to suggest the idea of oneness to the
mind, or it may be so loosely put together as to produce a confused and
indefinite impression. Ideas that have but little connection should be
expressed in separate sentences, and not crowded into one.
Keep long parentheses out of the middle of your sentences and when you
have apparently brought your sentences to a close don't try to continue
the thought or idea by adding supplementary clauses.