Increase production of headless puppets! (4,2)
I believe the answer is:
step up
'increase' is the definition.
(stepping up is a kind of increasing)
'production of headless puppets' is the wordplay.
'production of' indicates anagramming the letters.
'headless' means to remove the first letter.
'puppets' with its initial letter removed is 'uppets'.
'uppets' anagrammed gives 'STEP-UP'.
(Other definitions for step up that I've seen before include "To be promoted" , "Increase as with pace - or ascend stair?" , "Approach" , "Advancement (on a ladder or career)" , "Come forward" .)