Trinket (gold) for one in good books (6)
I believe the answer is:
bauble
'trinket' is the definition.
(I know that trinket can be written as bauble)
'gold for one in good books' is the wordplay.
I cannot really see how this works, but
'gold' could be 'au' (Au is the chemical symbol for gold) and 'au' is located in the answer.
'books' could be 'bb' (an abbreviation for book written twice) and 'bb' is found within the remaining letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for bauble that I've seen before include "Christmas tree decoration" , "'Bead, trinket (6)'" , "Gaudy toy" , "Showy trinket" , "Showy but valueless ornament" .)