One after another tries with aim amiss (8)
I believe the answer is:
seriatim
'one after another' is the definition.
('seriatim' can be a synonym of 'one after another')
'tries with aim amiss' is the wordplay.
'with' is a charade indicator (letters next to each other).
'amiss' indicates anagramming the letters.
'tries' after 'aim' is 'aimtries'.
'aimtries' anagrammed gives 'SERIATIM'.
(Other definitions for seriatim that I've seen before include "in succession" , "followed by another one" , "Formally, one after another" , "Point by point" .)