Be successful in shortening the thing? (3,2)
I believe the answer is:
cut it
'be successful' is the definition.
I know nothing about this answer so I cannot tell whether this works.
'shortening the thing?' is the wordplay.
I cannot really see how this works, but
'shortening' could be 'cut' (cut is a kind of shortening) and 'cut' is present in the answer.
'thing?' could be 'it' and 'it' is found within the answer.
This accounts for all the letters.
This explanation may well be incorrect...
'in' is the link.
Can you help me to learn more?
(Other definitions for cut it that I've seen before include "downsizing computer department?" , "manage" , "Meet standards" , "met requirements" , "Succeed" .)