Seller returning titled works, first of sketches included (9)
I believe the answer is:
tradesman
'seller' is the definition.
(eg a market trader)
'returning titled works first of sketches included' is the wordplay.
'returning' says the letters should be written in reverse.
'titled' becomes 'named' (similar in meaning).
'works' becomes 'art' (I've seen this before).
'first of sketches' becomes 's' (1st letter of 'sketches').
'included' indicates putting letters inside.
'named'+'art'='namedart'
'namedart' enclosing 's' is 'namsedart'.
'namsedart' in reverse letter order is 'TRADESMAN'.
(Other definitions for tradesman that I've seen before include "Ten dramas for skilled workman" , "One buying and selling" , "Buyer/seller of goods" , "Skilled hand" , "Business operator" .)