Stick with a few solid books, take any effects that suit your fancy, and adapt them for your purposes.
I wrote a mentalism act that runs one hour in length and the demonstrations all come from 13 Steps (Corinda) and PRISM (Max Maven), with a few added aspects from Psychological Subtleties (Banachek). Just with those three books, I have the means to write several hundred more shows, each different from the others. What I mean to say is that you are right in not focusing too heavily on one-shot muskets, so to speak. The act can play for 10 people or 2000 - with minor alterations - which is the beauty of mentalism.
There are a few words of caution that I'd like to offer, however:
First (and MOST importantly), you must accept that your act will die a few times in the beginning. Normally, this is the signal for the hobbiest to save up money and buy a better trick. Don't make that mistake. If you do, you'll simply write another act that will suffer the same fate, because it wasn't given time to mature. Seven years ago, I came to this site, and I was buying new tricks rather often, since I got bored of practicing the old ones. I was also disheartened every time I discovered that the tricks (despite my sleight of hand practice) weren't garnering the applause and awe that I had hoped. Only many years later did I learn that magic depends on theatrics above everything else, and that theatrical pursuits are matters of constant trial and error, as are all endeavors in life. One doesn't come to a new job hoping that he's practiced enough to complete each task perfectly on the first day. One doesn't practice driving in his driveway day after day and end up a master of the road. Everything requires a balance of practice and public critique. The years I spent becoming proficient at sleight of hand have shown their worth, but I wish I'd spent half of them out in the world performing. One always learns faster by doing. I recall an acting coach of mine once saying,
"You'll learn more in five minutes of actually acting than you will in one week of thinking about how you might do it."
and that has been true in my life for every single undertaking that has ever stricken my fancy. It could not be more true for magic and mentalism. Never ever EVER become disenchanted by a show that was a "failure." Every show is an evolution of the last, and every phenomenal show began as a failure. If this weren't true, everyone would be as successful as David Copperfield or Lance Burton or Penn and Teller. As Lance Burton would say, "You need to find your Hamburg," meaning that you need to find a place where you can perform regularly so that your act may evolve. Just as one wouldn't raise a child in a minefield, so should one avoid letting a show evolve in one's own privacy (or the company of other magicians, to be honest - magicians want one thing, but the laypeople who pay for tickets often desire things that would bore any magician to death).
Second, remember that nothing is successful if presented poorly. This is the reason that so many magicians must cue their applause with amateur lines such as, "Usually people clap at this point." Too many magicians make the mistake of presenting something without a clean ending - that is to say an ending that is unquestionably THE END of the routine. This is even more of a risk in mentalism acts, I find. So always always always make sure that your demonstrations end quickly after the climax, so as to offer the audience an ideal and evident opportunity to applaud. Everything in mentalism is focused on presentation, because the audience cannot understand the act through sight alone. This calls for a DEFINED personality or character. I am getting carried away. The point is that verbal presentation is key in mentalism, more so even than in most sorts of magic.
Third, everything that happens on a stage is a form of theater. The most successful magic and mentalism shows are those that have a firm foundation in theatrical conventions. A show that has no theatrical foundation is easily identified by an audience, but not because that audience knows about magic or theater - the audience can distinguish a theatrically lacking show because it knows what it expects to see as part of a stage production, which is to say suspense, plot, personality, movement, and sound! Above all, a great performer is defined by how much of him or herself is evidenced in his or her work. If your act resembles a horoscope reading, there is work to be done. If, however, it resembles an autobiography, you may just have achieved art.
I apologize if I have digressed, but I feel that the lessons I've learned may offer you some direction, or at least some things to consider. Don't read this with the intention of incorporating it into your first constructed act. That won't help you in the least. These things are always better when learned on one's own. I simply offer my experience as reassurance that these are the things that all solo performers must face in order to achieve any level of positive recognition, and hopefully to save you from blaming a bad show on your not being cut out for the stage. Build your first act however you think works for you: write a script or wing it; use a microphone or just your own voice; rehearse or improvise. Do whatever feels natural (you will learn) but in any case, perform!