Work too hard at making deliveries for a party (6)
I believe the answer is:
overdo
'work too hard' is the definition.
(I've seen this in another clue)
'deliveries for a party' is the wordplay.
'deliveries' becomes 'over' (I've seen this before).
'for' is a charade indicator (letters next to each other).
'a party' becomes 'do' (do can informally mean a party).
'over'+'do'='OVERDO'
'at making' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for overdo that I've seen before include "Exaggerate; use too much of" , "Exhaust" , "Be excessive, perhaps in cooking food" , "Maybe burn" , "Take too far" .)