Good line to develop (4)
I believe the answer is:
grow
'develop' is the definition.
(I've seen this before)
'good line' is the wordplay.
'good' becomes 'g' (abbreviation).
'line' becomes 'row' (row is a kind of line**).
'g'+'row'='GROW'
'to' is the link.
(Other definitions for grow that I've seen before include "Develop; increase" , "Mature" , "Burgeon" , "Expand" , "Get bigger" .)