Keep going to the back of the queue (4)
I believe the answer is:
last
'keep going' is the definition.
(I've seen this in another clue)
'the back of the queue' is the wordplay.
'the back of' shows that the letters should be reversed in order (I've seen 'back' mean this).
'the' becomes 't' (the is pronounced as a 't' sound in some dialects).
'queue' becomes 'sal' (I can't justify this - if you can you should give a lot more credence to this answer).
't'+'sal'='tsal'
'tsal' in reverse letter order is 'LAST'.
'to' is the link.
Can you help me to learn more?
(Other definitions for last that I've seen before include "Cobbler's model shape" , "Bringing up the rear" , "Endure - this clue is!" , "Rearmost" , "Shoemaker's shape" .)