Personally I'd say let it become known by becoming known yourself and letting people find out you sell some of your tricks. But I seem to be in a minority these days.
Well, there are more of us than the under 30 crowd wants to think. . . ;-)
Why are you so eager to sell something you have an exclusive on, right now?
I know Mentalists that pay thousands of dollars for a couple of sheets of paper, just so they have an exclusive impossibility for their show; it's the same as comedians buying lines from professional comedy writers. I even have people throw money in my direction from time to time because I've had an epiphany of a routine that would work well for them given their personality and performance style. They don't always agree or take my suggestion, but they always appreciate getting first dibs on something unique.
I'm helping a new name to the scene make his mark (Homer Arcana --
ESP Arcana). Very few people in the general magic world know this guy at all and yet, he's been a consultant for Alain Nu, Jerome Finley and others for a few years now; it actually took Alain a great deal of effort to get Homer to publish this particular manuscript, which I have given honest kudos over. . . it's awesome! Know what's attached to it and soon to follow makes it even more awesome but the point is, Homer just loves Mentalism and isn't out chasing $$$ signs or false fame. He's earned a reputation as a thinker and philosopher and then as the innovator that puts his personal beliefs into the product he's created.
I've been involved with magic forever it seems but it's only recently that I've decided to go that next step and market physical props, the first hitting the market (all going well) in September of this year (there about). Not everything has to do with Mentalism in that I did traditional magic for decades -- big illusions and family programs and so there will be a lot of stuff from that world. . . effects that haven't been seen in more than 20 years and which were MINE, no one else had them.
I could make a long list of effects made famous by other magic legends like Shimada's Dove on Cane or Peter Pit's Long Salt Pour that were kept exclusive until the artist was both, a legend and prepared to move to that next stage in his/her life.
I Do Understand the sad fact that many in today's magic culture believe that theft is their right; if you don't publish your effect & method and get it established as your own, then anyone can publish it and call it theirs and screw you out of bragging rights and in some instances, the legal right to perform your own effect. It's disgusting that magic (all industry) has become this unethical and immoral but it is a reality we must deal with and which leaves us with that quandary when it comes publishing and marketing an effect and which brings us to the next, proven step -- submit your idea to a noted publication like MAGIC, GENII, TOPS or even an on line source like VANISH so that an official publishing date can time stamp the piece, giving you historic credence should anyone else produce a similar effect.
But I Don't Make Any Money That Way! Screams the greed driven ego. . .
Not at first, but the more contributions of this sort you make the bigger your name becomes as a recognized and trusted innovator and thinker. Within reasonably short time you will be seen as a "go to" person by others and so you can become a consultant (unpaid initially but in time cash offers will come) and with a bit more time you'll be able to publish an eBook explaining a single effect, that people willing pay $60.00 or more for simply because they trust what you have to say vs. the $25.00 you MIGHT get on the same material right now, in that no one knows who you are. . . $60.00 and lots of sales or $25.00 and nominal sales at best? Which sounds the more logical?
There's a person on this forum who asked me and a few other notables in the Mentalism community about a routine he's been selling on the side. He's miffed over the fact that the pros have slammed the material and called it impractical and incomplete while he's managed to get positive kudos for it from the dozen or so folks that have purchased it. But he's not seeing the bigger picture, he's seeing only what he wants to see, allowing his ego to manipulate him vs. his gut -- his ability to accept constructive criticism that would result in a superior product, had he followed it. This is the other side about taking your time before releasing a piece, it allows you to work ALL the bugs out and turn it into a miracle vs. a trick.