Hotel sign including everything to indicate quality (8)
I believe the answer is:
hallmark
'quality' is the definition.
(hallmark is a kind of quality)
'hotel sign including everything' is the wordplay.
'hotel' becomes 'h' (phonetic alphabet: alpha, bravo, charlie etc.).
'sign' becomes 'mark' (mark is a kind of sign).
'including' means one lot of letters goes inside another.
'everything' becomes 'all' (all things).
'h'+'mark'='hmark'
'hmark' enclosing 'all' is 'HALLMARK'.
'to indicate' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for hallmark that I've seen before include "Official stamp" , "Sign of authenticity or excellence" , "It indicates the standard of precious metals" , "Distinctive attribute" , "Sign of authenticity (eg of silver)" .)