Fool first to help (6)
I believe the answer is:
assist
'help' is the definition.
(assisting is a kind of helping)
'fool first' is the wordplay.
'fool' becomes 'ass' (ass is a kind of fool**).
'first' becomes 'ist'.
'ass'+'ist'='ASSIST'
'to' is the link.
(Other definitions for assist that I've seen before include "Help member" , "Give help" , "Expedite" , "Be helpful to" , "Pitch in" .)