A new piece of advice regarding appetiser (9)
I believe the answer is:
antipasto
'appetiser' is the definition.
(I've seen this before)
'a new piece of advice regarding' is the wordplay.
'a new' becomes 'an' (I've seen this in other clues).
'piece of advice' becomes 'tip' (I've seen this before).
'regarding' becomes 'asto'.
'an'+'tip'+'asto'='ANTIPASTO'
(Other definitions for antipasto that I've seen before include "Starter course in an Italian meal" , "Italian appetiser" , "course leader" , "part of meal" , "course of hors d'oeuvres" .)