Perform for every favourite, adding value (10)
I believe the answer is:
perpetrate
'perform' is the definition.
(I've seen this before)
'every favourite adding value' is the wordplay.
'every' becomes 'per' ('per' means 'for each' or 'for every').
'favourite' becomes 'pet' (synonyms).
'adding' means one lot of letters go next to another.
'value' becomes 'rate' (both can mean to esteem).
'per'+'pet'+'rate'='PERPETRATE'
'for' is the link.
(Other definitions for perpetrate that I've seen before include "Be responsible for" , "Carry out, commit" , "perform" , "Commit (a bad action)" , "Commit (crime)" .)