4. Verb tenses. This is tricky. But in general: if something is always true, use the present tense. If it was always true once, use the past, or “would” plus past tense to indicate continuous action in the past. (“Every day, he’d go to the laundromat.”) . If it’s something happening before the time we’re in, use the past perfect (“He’d gone.”) Only the author knows the time flow – an editor can query, but the author must decide. If tenses are disjunct, there should be a very good reason. (Maybe the character is having a breakdown.) See also the use of the historical present. (“So, he goes, “What’re you doing?” and I go, “Butt out,” and he … etc.) Elmore Leonard is an expert at this kind of thing, and at informal dialogue in general.