Careful and attending to every detail (8)
I believe the answer is:
thorough
'careful and attending to every detail' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for thorough that I've seen before include "Meticulous - exhaustive" , "Complete - painstaking - unqualified" , "Rigorous" , "Downright" , "Painstaking; absolute" .)