Not citing sources in this instance is plagiarism. Use direct quotes sparingly. Quotes should be used to enhance what you are writing, not say it for you. Avoid jargon, cliches, slang, and abbreviations in a professional paper. State your ideas clearly and concisely.
Nothing ruins good writing like overwriting.
After you have edited your paper, read it aloud. If it does not sound the way you want then you need to do more editing. Write in complete sentences. Avoid run-on sentences. Avoid the overuse of commas.