If you want a tow-headed charmer, move smartly (6)
I believe the answer is:
twitch
'move smartly' is the definition.
'twitch' can be an answer for 'move' (twitching is a kind of moving). I'm not certain of the 'smartly' bit.
'if you want a tow-headed charmer' is the wordplay.
I cannot really see how this works, but
'charmer' could be 'witch' (someone who charms) and 'witch' is found in the answer.
A single letter 't' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for twitch that I've seen before include "Uncontrolled, jerky motion" , "Quiver or jerk spasmodically" , "Spasmodic jerk" , "Pang, tic" , "Sudden jerk" .)