Organise, build up (9)
I believe the answer is:
structure
I believe this clue is a double definition.
'organise' is the first definition.
(I know that structure is a more specific form of organise)
'build up' is the second definition.
(thesaurus)
(Other definitions for structure that I've seen before include "Edifice" , "Building; framework" , "Building or organised arrangement" , "make-up" .)