Go too far concerning party (6)
I believe the answer is:
overdo
'go too far' is the definition.
(I've seen this in another clue)
'concerning party' is the wordplay.
'concerning' becomes 'over' (both can mean relating to).
'party' becomes 'do' (do is a kind of party).
'over'+'do'='OVERDO'
(Other definitions for overdo that I've seen before include "Cook wrongly" , "Perform excessively" , "Sum of a persons actions (Hinduism)" , "Maybe burn" , "Use to excess" .)