Endeavour to secure last piece - it's all the rage (6)
I believe the answer is:
trendy
'all the rage' is the definition.
(I've seen this in another clue)
'endeavour to secure last' is the wordplay.
'endeavour' becomes 'try' (synonyms).
'to secure' indicates putting letters inside (inserted letters are secured inside).
'last' becomes 'end' (I've seen this in another clue).
'try' enclosing 'end' is 'TRENDY'.
'piece it's' is the link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for trendy that I've seen before include "Voguish" , "Up to date, fashionable" , "following latest convention" , "Consciously fashionable" , "Informally, following the fashions" .)