Contracted big town dude to come up with scheme (6)
I believe the answer is:
tactic
'scheme' is the definition.
(I've seen this in another clue)
'contracted big town dude to come up' is the wordplay.
'contracted' means to remove the last letter (to contract is to shorten).
'big town' becomes 'city' (I've seen this before).
'dude' becomes 'cat' (American slang for man, esp in Jazz).
'to come up' is a reversal indicator.
'city' with its last letter taken off is 'cit'.
'cit'+'cat'='citcat'
'citcat' written backwards gives 'TACTIC'.
'with' acts as a link.
(Other definitions for tactic that I've seen before include "Manoeuvre designed to outwit enemy" , "Device" , "Action aimed at a specific end" , "element of strategy" , "Ruse, strategy" .)