Firstly, are you going to be a Magician or a Mentalist?
Contrary to popular conjecture, there is a HUGE difference in the two and thus, a big difference in how the public will perceive you. If they see you doing coins across or sponge balls one minute and then trying to apparently read their mind the next, they aren't going to buy into the idea that you are psychic or some kind of "expert" in some unique field involving memory, hypnosis, suggestion, body language, et al. YOU WILL BE SEEN AS A MAGICIAN SPEWING A LINE OF BULL.
There is absolutely nothing wrong with a magician doing a few bits of mentalism here and there but if you want it to come across as "deep' and "meaningful" YOU have to commit to that side of the craft and become a mentalist... that is to say, you must be your best illusion. This is what the old timers & spiritualists did (and most of the more successful ones still do), and it is the "Big Secret" when it comes to successful mentalism whether it's a hobby or a career.
Secondly, there is one single "effect" in mentalism that will give you as much depth, feeling, and emotional connection as you could even imagine IF you have the guts to do it and do it right -- READINGS! This is the one thing people come to experience when someone calls themselves as "Mentalist"/Mind Reader or whatever it may be. The Q&A, even by Corinda's standards, is the most potent of all skills in the whole of Mentalism. Sadly, most that move into mentalism from the magician's world hold a bias both, against the practice but likewise, in what being a Reader is really about... and you will notice that I've not yet said "Cold Reading" and that's deliberate; Cold Reading is a term that has been grossly misused in recently years and given a myriad of sub-sets... that is the kind way of saying that it's been made far more difficult and confusing than it needs to be. So if you have the balls to actually learn how to READ PEOPLE and do so in practice, you will have found that elusive bit you're looking for. But you must turn off that magician's voice in your head to be successful... just ask guys like Mark Strivings, John Riggs or Richard Webster if you doubt me.
To become a solid Reader STAY AWAY FROM THE MAGIC BOOKS PERTAINING TO THE TOPIC... at least for the first 6-9 months (and that includes my books as well). You need to learn how to work with a couple of actual systems based on how every shut-eye student learns them. This is the only way you will be able to see how effective they/you can be without a head-full of theory and hogwash that's been written by people who've never done Readings for a living... and yes, that includes the much heralded Mr. Rowland.
Though I've done Tarot Readings since I was 16 if I had to do it all over again, I'd started with Numerology and Palmistry for two very simple and logical reasons; most everyone you meet has a name and birth-date as well as one or two hands; with nothing other you can do a very solid 20-60 minute Reading for that person using nothing but those two disciplines and using them in the legitimate manner -- how they've been taught to shut-eye students for generations. But there is one other important thing to consider here; Palmistry in particular, has some very valid scientific support to it. It is still part of medical training... kind of... the techniques that have been known to palmists for ever, are the same things doctors & nurses look for in the hands, tissue and nails when figuring out this or that condition in a patient {see:
"Beyond Palmistry" by Beverly Jaegers (a 3 book series) -- and it's companion texts; Beverly is an RN as well as a Palmist so her insights are quite unique}
As to the Numerology thing... it's simply practical and can be used in a myriad of ways. The simplest place to learn this from is the only magic-based resource I'm going to encourage as a starting point; "Psychometry from A-Z" by Richard Webster. Richard has several very solid books and audio tapes on the topic of Readings for both, the magic/mentalism and shut-eye markets;
here's a few I'd think all of you would have fun with...
I Did Say Something About "Doing It", Didn't I?
Don't approach it as a "Trick", take it serious. Perhaps you've been having some fun with folks doing some magic; break that process by talking about how tricks are fun but don't explain things for you (as an example) and how you've started looking at how things, like Palmistry, have real world applications and because of this, there must be more to it than meets the eye... now move into doing some simple Readings relying only on the basics of Palmistry (this will evolve as you study).
After you've done a few dozen Readings your confidence will grow and of course, by continued study, so will your skill level. In time you will see how you can blend insights based on their numerology into a palm Reading. If you use the Webster book I've suggested, you will have more than enough in way of canned information that can be sewn into your patter.
BUT IT'S STILL COLD READING?!
Yes and NO... but that's part of the subject I'll not dive into just yet. I want to look at your question and the challenge to find "deeper" mentalism... the next "Trick" on the list is MUSCLE READING
Pick up Disc III of Banachek's PSI Series along with his book Psychophysiological Thought Reading and you'll have an excellent start. There are other bits of material on this topic but the only other magic based publication I can recommend is the Eric Van Hanussen book. Once you have "mastered" the material in these primer sources, then you can move into other aspects of the work. But while you are practicing this I'd suggest you also study
Dowsing (that link goes to Richard Webster's books on the subject), in that it is one in the same except it introduces you to Pendulums and Divining Rods.
A SUMMARY
The two things I've given here are the two primary skill-sets that most all spiritualists and early year Mentalists relied upon. Not gimmicks or slight of hand, but two skill sets that are about as real as real can get. The third "natural" skill set they would cultivate is memory and though I have a horrid one that's in decay I can assure you that memory skills are vital in Mentalism and if you can adapt a mnemonic formula as part of a verbal code, you'll be a million miles ahead of the rest... but then I do mention this in my
Easy Reading book (not currently available).
The first "tricks" you'll find in the old timer's arsenal were Billets and Nail Writers. When you add two such simple/subtle tools to the arsenal noted above, you can start your own religion. I'd hope that would be deep enough for anyone.