What you should avoid 1.You do not have to try to impress people by using words most people have never heard of. Many published articles are like this, and they are poor papers on account of it. 2.Do not use colloquial speech, slang, or "childish" words or phrases. 3.Do not use contractions: for example, "don't" must be "do not" and "isn't" must be "is not" etc.