Listen, playing it adds the sparkle to Christmas (6)
I believe the answer is:
tinsel
'it adds the sparkle to christmas' is the definition.
The definition suggests a singular noun which matches the answer.
'listen playing' is the wordplay.
'playing' indicates an anagram.
'listen' is an anagram of 'TINSEL'.
Can you help me to learn more?
(Other definitions for tinsel that I've seen before include "Glittering Christmas strip" , "Enlist the glittering decoration" , "Inexpensive sparkly stuff" , "At Christmas it might be seen" , "Listen (anag) - yarn interwoven with glitter" .)