Approach rankings' top fly-fisher (6)
I believe the answer is:
angler
'fisher' is the definition.
(angler is a kind of fisher)
'approach rankings' top' is the wordplay.
'approach' becomes 'angle' (as in a journalist's approach to a story).
'top' says to take the initial letters (in a down clue, the first letter is top).
The first letter of 'rankings' is 'r'.
'angle'+'r'='ANGLER'
'fly' acts as a link.
I am not very happy about this link. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for angler that I've seen before include "He fishes with rod and line" , "One hoping for a catch" , "who looks for compliments" , "Hook and line fisherman" , "Fisher with rod and line" .)