With the exception of a very few magicians who have 
played a specific character and were very good 
actors, the best advice is to play yourself, but, of 
course, with magic powers.  All good magic requires 
acting and Robert-Houdin's definition of a conjuror as 
"an actor playing the part of a magician" is as true 
today as it was 125 years ago.  Many of the "sleights" 
and "moves" of magic are not things that we would do 
naturally, but they must be thoroughly learned and 
acted so that they áððåáò natural.  For only by 
seeming natural will they be unnoticed.  Along with 
natural acting as a requirement for producing illusion, it 
is also important not to try to be something you are not.  
If you "think funny" and have a natural flair for humor, 
weave it into your repertoire with "comedy patter" and 
sight gags.  If comedy does not come naturally to you, 
then stick with the humor that is often inherent in the 
performance of magic.  The old-time magicians called it 
"laughter born of bewilderment."