Amir,
Great question.
One of the advantages of being a mentalist is the ability to work with minimal props, yet to great effect.
The illusion to the audience should be of you reading their minds, with little to no help in the process.
Drawing duplication, book tests, telling someone something about themselves that no one else there might know, nailing someone's license plate number, name of their dog or whatever, is something that will play really big for an audience.
Back when, Hal Holbrook did a one man show playing Mark Twain. One guy, a chair, table, background and a cigar. He held the audience spellbound for almost 2 hours!
Just telling stories, making quips and social commentary as Twain would have, based on his writings, he won award after award, got a national TV special and more from this "simple" concept.
As a mentalist, one should be able to do the same and (while not as well, probably - Hal Holbrook is one helluvan actor) with similar effect on the audience.
But mentalism has been called the most difficult of the magical arts to perform for just that reason - there are no props to prop you up and to distract the eyes and imaginations of the audience. It's just you and them.
Making it convincing and emotionally connecting with the audience is the really tough part, not looking at the little piece of paper you might be hiding in your hand.
Uri Geller played to crowds of thousands while just bending keys and spoons. Dunninger did it on radio!
Work to your strengths and do your best to convey to every member of the audience the emotional impact of what you are doing and almost whatever you perform CAN play big.
It depends on you.
Need I say more?
Lee Darrow, C.Ht.
http://www.leedarrow.com