Here is a superb piece in the Guardian on how to write the perfect sentence. It references a piece by Gary Lutz - The Sentence is a Lonely Place - part of which is below.
The sentence, with its narrow typographical confines, is a lonely place, the loneliest place for a writer, and the temptation for the writer to get out of one sentence as soon as possible and get going on the next sentence is entirely understandable. In fact, the conditions in just about any sentence soon enough become (shall we admit it?) claustrophobic, inhospitable, even hellish. But too often our habitual and hasty breaking away from one sentence to another results in sentences that remain undeveloped parcels of literary real estate, sentences that do not feel fully inhabitated and settled in by language. So many of the sentences we confront in books and magazines look unfinished and provisional, and start to go to pieces as soon as we gawk at and stare into them. They don’t hold up. Their diction is often not just spare and stark but bare and miserly.