But unless you're a writer, don't do major copy surgery yourself. Writing should be repaired by writers. Don't play schoolteacher. Amateur grammarians should not be allowed to rewrite copy. They don't realize that professional writers deliberately break grammatical rules and use unorthodox stylistic techniques to make copy lively and readable.
Sentence fragments can generate greater impact.
Sentences ending with prepositions sound more natural. Starting sentences with conjunctions makes for a quick, smooth transition between thoughts. Don't deprive copywriters of the tools they use to make your copy flow and glow with warmth and personality. If you want correct grammar, teach high-school English. If you want great copy, let the copywriter decide.