Female teacher with favourite raised error (7)
I believe the answer is:
misstep
'error' is the definition.
(misstep can mean an error or mistake)
'female teacher with favourite raised' is the wordplay.
'female teacher' becomes 'miss' (a female teacher might be addressed 'miss').
'with' means one lot of letters go next to another.
'favourite' becomes 'pet' (synonyms).
'raised' says the letters should be written in reverse (going up in a down clue).
'pet' written backwards gives 'tep'.
'miss'+'tep'='MISSTEP'
(Other definitions for misstep that I've seen before include "Badly judged move" , "False move" , "Error" , "bad move" , "Badly judged footing" .)