Try pirouettes without success in matching clothes (7)
I believe the answer is:
twinset
'matching clothes' is the definition.
(set of matching clothes)
'try pirouettes without success' is the wordplay.
'try' becomes 'test' (test is a kind of try).
'pirouettes' says the letters should be written in reverse (pirouette is a spin in ballet).
'without' means one lot of letters goes inside another ('without' can be similar in meaning to 'outside').
'success' becomes 'win' (I've seen this in another clue).
'test' written backwards gives 'tset'.
'tset' going around 'win' is 'TWINSET'.
'in' is the link.
(Other definitions for twinset that I've seen before include "clothing" , "Matching garments" , "Matching cardigan and jumper worn together" , "coordinated clothes" , "Wear associated with pearls?" .)