Keep going to the back of the queue (4)
I believe the answer is:
last
'keep going' is the definition.
(I've seen this before)
'the back of the queue' is the wordplay.
'the back of' is a reversal indicator (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 explain this - if you can you should give a lot more credence to this answer).
't'+'sal'='tsal'
'tsal' backwards 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" .)