I have to follow Eastern females, etc, being represented as useful (9)
I believe the answer is:
effective
'useful' is the definition.
('effective' is associated in meaning with 'useful')
'i have to follow eastern females etc being represented' is the wordplay.
'i have' becomes 'ive'.
'to follow' means one lot of letters go next to another.
'eastern' becomes 'e'.
'females' becomes 'ff' (I've seen this in other clues).
'being represented' indicates anagramming the letters.
'etc' with letters rearranged gives 'ect'.
'e'+'ff'+'ect'='effect'
'ive' after 'effect' is 'EFFECTIVE'.
'as' acts as a link.
(Other definitions for effective that I've seen before include "operative > producing the desired result" , "Accomplishing an objective, efficient" , "Striking" , "Producing results" , "Efficacious, efficient" .)