Usual trick, hiding ring and military medal (6)
I believe the answer is:
common
'usual' is the definition.
('common' can be similar in meaning to 'usual')
'trick hiding ring and military medal' is the wordplay.
'trick' becomes 'con' (I've seen this before).
'hiding' is an insertion indicator.
'ring' becomes 'o'.
'and' says to put letters next to each other (I've seen this in other clues).
'military medal' becomes 'mm'.
'o' after 'mm' is 'mmo'.
'con' enclosing 'mmo' is 'COMMON'.
(Other definitions for common that I've seen before include "Done by a number of people" , "Ill-bred, not refined in manner" , "Plentiful or vulgar" , "General - public" , "Shared ground" .)