Carry too far because of big party (6)
I believe the answer is:
overdo
'carry too far' is the definition.
(I've seen this before)
'because of big party' is the wordplay.
'because of' becomes 'over' (eg 'he's upset over it').
'big party' becomes 'do' (do is a kind of party. I am not sure about the 'big' bit.).
'over'+'do'='OVERDO'
Can you help me to learn more?
(Other definitions for overdo that I've seen before include "Carry to excess" , "Be excessive, perhaps in cooking food" , "Cook wrongly" , "Exaggerate, go too far" , "Exaggerate; use too much of" .)