Actually, how much experience do you have on stage working with a real audience?
Mentalism IS NOT the same as doing magic, it requires some serious showmanship skills as well as people management ability; being able to size folks up so you have an informed idea as to who will be best for this or that routine or even what part of a routine that you are planning to do.
You also need to create a theme -- a Claim as we usually refer to it -- What Are Your Abilities?
Contrary to what many in today's world tend to do, making too many claims and trying to demonstrate too many abilities makes you look like a cheap magician vs. Mind Reader or even an educated intellect presenting demonstration in some form of Mind Science or Behavioral study. Uri Geller rarely does much more than his PK work and a bit of Premonition/Clairvoyance and he's one of the most successful Psychic Entertainers of the past 50 years. In other words, Less is More! This is a problem for most younger performers because they're chasing an ego-concept; this effect will make be look cool as will this one and this one. . . they get an array of effects that aren't interrelated and which do not follow a logical pattern that is anchored by a theme/claim.
What Do You KNOW When it Comes to Mentalism?
What's your skill level when it comes to doing Readings, working Billets, working with Secret Writing techniques or doing Pre-Show?
Building any kind of show requires a great deal of thought along these lines that includes tradition magic as well as someone doing mime or juggling. . . a plan must exist as a starting point so that you can build the program in an effective manner that takes the audience on an adventure of sorts. Magic is not just grabbing a pile of tricks off the shelf and calling it a show and when it comes to Mentalism, doing such a thing is akin to slashing your wrist.
Why Do You Want to Mimic Acts That Exist?
There are so many Derren Brown clones out there (especially in the UK) that they are barely in demand now days, bookers are looking for something that's different, more daring and not a cheap imitation. So be yourself -- YOU ARE THE PRODUCT! Create a program that employs your personality and philosophy rather than going along with the proverbial flow. Dare to contradict the popular or intellectual message that's so overdone in today's mentalism market. But stand out from the crowd.
If You Have Not Read Corinda & Annemann at Least Twice. . . you're probably not ready.
If you Have Yet to Learn at Least 30% of the Techniques in Those Books . . . you're not ready
If you Have Yet to Perform Regularly for a General Audience of People for at Least a Year. . . you're not ready.
I'm not out to stifle you or crush your vision, only to splash some ice water in your face and give you some facts and the guidelines you've asked about. Start now working towards that dream but start small; learn solid skills when it comes to sizing people up as well as "Cold Reading" so you can simply walk in on a total stranger and offer them insights into their lives. Learn how to work with billets; you should know at least 3-5 different switching methods and as many techniques for coping the read. You should know and be competent with the key Peek systems like Acidus Novus as well as the variations to the Center Tear (I strongly recommend T-Rex by Ran Pink and Dr. Bill's Tear). You should study the classics as well such as Cassidy's 4th Dimensional Telepathy and the various ways of getting into a Q&A or even Psychometry styled Reading (the stuff audiences want to experience and so, the stuff that will get you paid).
Don't be eager to throw your money away, if you have the following books on your bookshelf, you have more than you'll ever need for a full career;
13 Steps to Mentalism
Practical Mental Magic
Fundamentals by Bob Cassidy
Theories & Methods for the Practical Psychic by Bob Cassidy
Switchcraft by Elliott Bresler
The Gentle Art of Cold Reading by Lee Earle
Psychometry from A-Z by Richard Webster
The Real Work of Cold Reading by Bob Cassidy
The Tarot Reader's Notebook by Ron Martin
Psychophysiological Thought Reading by Banachek
~Disc 3 of the PSI Series DVD Collection
Mind Reading & Telepathy by Eric Jan Hanussen
Psychological Subtleties by Banachek (all 3 volumes)
There are a few other titles but this will get you started.