Professional way of working produces publicity piece (5)
I believe the answer is:
promo
'publicity piece' is the definition.
(I've seen this in another clue)
'professional way of working' is the wordplay.
'professional' becomes 'pro' (abbreviation).
'way of working' becomes 'mo' (abbreviation for modus operandi).
'pro'+'mo'='PROMO'
'produces' acts as a link.
(Other definitions for promo that I've seen before include "Encouragement" , "21 [TRAILER]" , "for [a] little while" , "Ad" , "Brief publicity" .)