Angle to capture heart of pretty thing (6)
I believe the answer is:
fetish
'thing' is the definition.
(thesaurus)
'angle to capture heart of pretty' is the wordplay.
'angle' becomes 'fish' ('fish' can be a synonym of 'angle').
'to capture' is an insertion indicator.
'heart of' means to look at the middle letters.
The middle letters of 'pretty' are 'et'.
'fish' going around 'et' is 'FETISH'.
(Other definitions for fetish that I've seen before include "charm" , "Object of unreasoning devotion" , "Object worshipped by primitive people or fixation (6)" , "magical object" , "Object worshipped by primitive people or of abnormal sexual interest" .)