Margaret, a very good type, a right “superperson” (8)
I believe the answer is:
megastar
'superperson' is the definition.
'margaret a very good type a right' is the wordplay.
'margaret' becomes 'meg'.
'very good type' becomes 'st' (saint).
'a right' becomes 'ar' (I've seen this in other clues).
'meg'+'a'+'st'+'ar'='MEGASTAR'
(Other definitions for megastar that I've seen before include "famous entertainer" , "Great Sam (anag)" , "major celeb" , "Dazzlingly successful person" , "Very famous person" .)