Add a touch of sparkle as Judge Russell is up first (6)
I believe the answer is:
aerate
'add a touch of sparkle' is the definition.
I can't tell whether this definition defines the answer.
'judge russell is up first' is the wordplay.
'judge' becomes 'rate' (rating is a kind of judging).
'russell' becomes 'ea' (I can't justify this - if you can you should give a lot more credence to this answer).
'is up' says the letters should be written backwards (in down clue: letters go upwards).
'first' says to put letters next to each other.
'ea' back-to-front is 'ae'.
'rate' after 'ae' is 'AERATE'.
'as' acts as a link.
Can you help me to learn more?
(Other definitions for aerate that I've seen before include "Get bubbly" , "produce inflation?" , "Put air into" , "Add fizz" , "Pass bubbles through?" .)