Balls bowled by doctor do too much (8)
I believe the answer is:
overcook
'do too much' is the definition.
(I've seen this before)
'balls bowled by' is the wordplay.
'balls' becomes 'over' (I've seen this in other clues).
'bowled by' becomes 'cook' (I can't explain this - if you can you should believe this answer much more).
'over'+'cook'='OVERCOOK'
'doctor' acts as a link.
I am not very happy about this link. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for overcook that I've seen before include "Char" , "Make a bad hash" , "Do too much" .)