Including information already given in the same phrase.
Using a form of expression which is very common and boring.
Extremely exaggerated statement to cause an effect.
A comparison using 'like' or 'as'.
Writing the conclusion that someone is meant to come to, rather than encouraging them to infer it through argument or description.
Using descriptions of reality to lead the reader to understand your meaning without telling it outright.
A short list of three items.
Piece begins in one tense and then switches to another.
Staying in one tense through a whole piece.
Missing out letters, and using apostrophes to take their space. Not acceptable for formal work other than in speech or quotation.
Joining two clauses without a full stop or conjunction.
Accurate, logical vocabulary choices which add to the effect (NB
random words pulled from a thesaurus).