Cultivate favourable publicity about old hotel (6)
I believe the answer is:
plough
'cultivate' is the definition.
(I've seen this before)
'favourable publicity about old hotel' is the wordplay.
'favourable publicity' becomes 'plug'.
'about' indicates putting letters inside.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'hotel' becomes 'h' (phonetic alphabet: alpha, bravo, charlie etc.).
'plug' going around 'o' is 'ploug'.
'ploug'+'h'='PLOUGH'
(Other definitions for plough that I've seen before include "Soil-breaker" , "till" , "Seven stars on the farm?" , "Make furrows" , "Harrow?" .)