Bit of music -- not the first time it's done with a hook (7)
I believe the answer is:
crochet
'it's done with a hook' is the definition.
(craft activity done with a crochet hook)
'bit of music not the first time' is the wordplay.
'bit of music' becomes 'crotchet' (type of musical note).
'not' indicates named letters should be taken away.
'the first time' becomes 't' (1st letter of 'time').
'crotchet' with 't' removed is 'CROCHET'.
(Other definitions for crochet that I've seen before include "Craft product" , "Make using thread and hooked needle" , "Genteel pastime" , "In music, a note equal to half a minim" , "Type of needlework" .)