Just developing a style for children's stories (5,5)
I believe the answer is:
fairy tales
'children's stories' is the definition.
(stories for children)
'just developing a style' is the wordplay.
'just' becomes 'fair' (just can mean fair in the sense of showing justice).
'developing' is an anagram indicator (letters developed into a new form).
'a'+'style'='astyle'
'astyle' anagrammed gives 'ytales'.
'fair'+'ytales'='FAIRY-TALES'
'for' is the link.
(Other definitions for fairy tales that I've seen before include "Unbelievable stories" , "Perrault's works" .)