Practise tries again close to line (8)
I believe the answer is:
rehearse
'practise' is the definition.
('rehearse' can be a synonym of 'practise')
'tries again close to line' is the wordplay.
'tries again' becomes 'rehears' ('hears' can be a synonym for 'tries' so perhaps 'rehears' is OK for 'tries again').
'close to' suggests the final letters (the close/ending of).
The last letter of 'line' is 'e'.
'rehears'+'e'='REHEARSE'
(Other definitions for rehearse that I've seen before include "Practise play in theatre" , "Prepare for a stage production" , "Practice for the performance" , "Go over" , "prepare for performance" .)