American uncle goes up to bed, hoping this will bring him good luck (6)
I believe the answer is:
mascot
'luck' is the definition.
(thesaurus)
'american uncle goes up to bed' is the wordplay.
'american uncle' becomes 'Sam' (Uncle Sam is a nickname for the USA).
'goes up' says the letters should be written backwards.
'to' is a charade indicator (letters next to each other).
'bed' becomes 'cot' (cot is a type of bed).
'sam' in reverse letter order is 'mas'.
'mas'+'cot'='MASCOT'
'hoping this will bring him good' acts as a link.
This may not be right. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for mascot that I've seen before include "Good luck token" , "Symbolic lucky figure" , "World Cup Willie, say" , "Luck-bringer" , "Charm - talisman" .)