I would get in a row, being neater (6)
I believe the answer is:
tidier
'neater' is the definition.
('tidy' can be similar in meaning to 'neat')
'i would get in a row' is the wordplay.
'i would' becomes 'I'd'.
'get in' is an insertion indicator.
'a row' becomes 'tier' (a tier is a row of things).
'id' put inside 'tier' is 'TIDIER'.
'being' acts as a link.
(Other definitions for tidier that I've seen before include "straightened up?" , "more organised" , "More neat and orderly" , "Trigger" , "not so disorderly" .)