Side and corner shot? Think again! (10)
I believe the answer is:
reconsider
'think again' is the definition.
('consider' is an answer for 'think' so perhaps 'reconsider' is OK for 'think again')
'side and corner shot?' is the wordplay.
'and' is a charade indicator (letters next to each other) (I've seen this in other clues).
'shot?' is an anagram indicator.
'side' after 'corner' is 'cornerside'.
'cornerside' is an anagram of 'RECONSIDER'.
(Other definitions for reconsider that I've seen before include "Have second thoughts" , "Think again" , "Nice orders ( anag.)" , "Ponder further" .)