The first draft can be written quickly, as it is for substance and arguments, which can be refined with each succeeding draft. In later drafts you can concentrate on polishing your style. Academic essays are usually written in formal style. Thus you should generally avoid contractions and colloquialisms unless the subject matter particularly calls for such usage. Good academic writing is formal, but also lively and direct.
Verbosity is demonstrated more often than brevity.
Good writing is also precise. Try to choose words that express your intention exactly. Modern academic style requires care and precision in the use of language regarding race and gender. Just as you would avoid racist slurs and words that convey old-fashioned racial stereotypes, it is important to avoid phrases and words that are gender exclusive, unless you consciously intend them to be so. Remember to number all pages.