It rises twice over an artist of fame (6)
I believe the answer is:
titian
'artist of fame' is the definition.
'titian' can be an answer for 'artist' (16th-century painter). I'm not certain of the 'of fame' bit.
'it rises twice over an' is the wordplay.
'rises' is a reversal indicator.
'twice' indicates the doubling of some letters.
'over' says to put letters next to each other (in a down clue, some letters go over others).
'it' written backwards gives 'ti'.
'ti' duplicated is 'titi'.
'titi'+'an'='TITIAN'
Can you help me to learn more?
(Other definitions for titian that I've seen before include "Sixteenth century Venetian painter" , "Venetian fifteenth-sixteenth century painter" , "Italian 16th-century painter" , "artist from Venice" , "Painter; red tint" .)