Shape nearly everything according to established style (6)
I believe the answer is:
formal
'established style' is the definition.
'formal' can be an answer for 'established' (thesaurus). I'm not certain of the 'style' bit.
'shape nearly everything' is the wordplay.
'shape' becomes 'form' (synonyms).
'nearly' means to remove the last letter.
'everything' becomes 'all' (all things).
'all' with its final letter taken off is 'al'.
'form'+'al'='FORMAL'
'according to' is the link.
Can you help me to learn more?
(Other definitions for formal that I've seen before include "according to protocol" , "Regular" , "Befitting a person in authority" , "Ceremonious or prescribed" , "Conforming to accepted rules or customs" .)