From Writerisms and other Sins: A Writer’s Shortcut to Stronger Writing:

1. am, is, are, was, were, being, be, been … combined with “by” or with “by … someone” implied but not stated. Such structures are passives. In general, limit passive verb use to one or two per book. The word “by” followed by a person is an easy flag for passives.
2. am, is, are, was, were, being, be, been … combined with an adjective. “He was sad as he walked about the apartment.” “He moped about the apartment.” A single colorful verb is stronger than any was + adjective; but don’t slide to the polar opposite and overuse colorful verbs. There are writers that vastly overuse the “be” verb; if you are one, fix it. If you aren’t one—don’t, because overfixing it will commit the next error.

   and also:

3. -ness A substitute for thinking of the right word. “Darkness,” “unhappiness,” and such come of tacking -ness (or occasionally – ion) onto words. There’s often a better answer. Use it as needed.As a general rule, use a major or stand-out vocabulary word only once a paragraph, maybe twice a page, and if truly outre, only once per book.