SleightofCards, firstly, welcome back.
I think there are a few things that need to be said in regards to your post. Firstly, I will simply say this: before you perform mentalism, you must come to an understanding of what mentalism actually is. That is, get an idea of what's out there. So I would recommend that you simply do some research about mentalism, who's big at the moment, who have been the giants of the past, what they've written and done, etc. Just like any professional sportsman must know his sport inside and out, so too does the performer need to know his craft. Understand what you're performing, and how - things like persona, for example. Otherwise, you can't possibly do well with mentalism.
Secondly. The most recommended starting point for mentalists are twofold: 13 Steps to Mentalism, Corinda, and Fundamentals, Bob Cassidy. 13 Steps is a good resource to teach you just some of the things that can be done. It's an excellent instruction manual which gives you an overview of effects in various areas. Fundamentals teaches you how to be a mentalist, as well as mentalism effects, which is just as important. It's the Tarbell of mentalism, I would even go so far as to say.
Thirdly. Don't neglect the nail writing! I talk to a lot of magicians, and something a lot of people ask me is my routine: what do I perform, what do I open with, what do I close with. Actually, if you look in Corinda, look in Step One, the very first effect in Corinda, which consists of the spectator naming a number, and the mentalist nail writes the number and reveals it. That's my closer. And I tell magicians as much. And without fail, they say, "What? Is that your closer? It doesn't sound strong enough." And that's after I tell them how it's done. Before I tell them that, they all stand there agape, asking, "Is it 100%? Is the method for sale?" etc. That's my closer. If you read through the description, it's nothing. It's the sort of thing you read over and forget. But it's one of the strongest effects I perform. Why? Presentation. Especially with mentalism, presentation is so, so important. It's not "only" a nail writing trick. It's one of the hardest hitting effects I perform. Simply because I've created a good presentation out of it. So don't ever dismiss things simply because they look like they are too simple, or easy, or don't have potential. When you get down to it, all of the strongest effects in your repertoire will be the ones you take for yourself and dig out their potential from nowhere.