Black eyes for those who excel (7)
I believe the answer is:
shiners
'black eyes' is the definition.
('shiner' can be a synonym of 'black eye')
'those who excel' is the wordplay.
I cannot quite understand how this works, but
'excel' could be 'shine' (I've seen this in another clue) and 'shine' is present in the answer.
This explanation may well be incorrect...
'for' acts as a link.
Can you help me to learn more?
(Other definitions for shiners that I've seen before include "Fish with colourful markings" , "Black eyes (sl.)" .)