Pieces of duet lost points (6)
I believe the answer is:
etudes
'pieces' is the definition.
(etude is a kind of piece)
'duet lost points' is the wordplay.
I cannot quite see how this works, but
an anagram of 'duet' is 'etud' which is located in the answer.
'points' could be 'es' (E is an example) and 'es' is located in the answer.
This accounts for all the letters.
This may be the basis of clue (or it may be nonsense).
'of' is the link.
Can you help me to learn more?
(Other definitions for etudes that I've seen before include "Musical compositions (French)" , "Set due in short musical compositions" , "Short compositions for solo instruments" , "Sue Ted over short musical compositions" , "Musical studies" .)