Divide complex sentences into simple sentences. Your goal should be to mix short and long sentences until the paragraph has a readable rhythm. Too many short sentences strung together will make the paragraph sound choppy. Too many long sentence will lose the reader in a maze of language. The Elements of Style, William Strunk, Jr. and E.B. White.
Vigorous writing is concise.
A sentence should contain no unnecessary words, a paragraph no unnecessary sentences, for the same reason that a drawing should have no unnecessary lines and a machine no unnecessary parts. This requires not that the writer make all his sentences short, or that he avoid all detail and treat his subjects only in outline, but that every word tell.