Do excellent outside church night before festival? (7)
I believe the answer is:
achieve
'do' is the definition.
(I've seen this in another clue)
'excellent outside church night before festival?' is the wordplay.
I cannot quite see how this works, but
'church' could be 'ch' (common abbreviation) and 'ch' is present in the answer.
'excellent' could be 'ai' (resembles 'A1', old-fashioned term for excellent) and 'ai' is found in the remaining letters.
'night before' could be 'eve' (eve can mean the night before something) and 'eve' is found within the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for achieve that I've seen before include "Gain or reach by effort" , "Finish" , "Attain successfully" , "Bring to a successful outcome" , "Reach; be successful" .)