If you want a venture to be successful, then exploit an un-mined niche, unless you're a producer of Chilean made-for-TV movies, in which case you're better off exploiting a mined niche. Exploiting a void amidst ATX's booming screen-printing scene, Under Pressure.
Under Pressure's a full-service shop conceived by a pair of TX State grads after realizing nobody in town would print extremely limited-run t-shirts for customers bringing in their own ideas -- partly because they deemed it cost-ineffective, partly because the masses' ideas might expose them to the terror of knowing what this world is about. How it works: either BYO notion to their shop in the form of a photo or drawing, and they'll crank out any number you like on super-soft sweatshop-free garments, even if you only want one; or learn to DIY it at one of their two-hour workshops focusing on the basics of emulsion and print-making, as well as advanced techniques like 3D color and making glow-in-the-dark ink, even more useful now that you're too old to shop at Spencer's. Should you lack notions, they also sling their own designs, like the Rolleiflex featuring an old-school medium format camera, and a series detailing schematics of guitars, bikes, and the game of golf, a shirt Tiger would love...to take off his neighbor's daughter, but not 'till she turned 21, because otherwise there might be a scandal.
Their webshop also boasts a healthy selection of concert posters commissioned by fests like the Fun Fun Fun, national acts like Beach House and Chromeo, and local up-and-comers like Shearwater and Harlem -- trying to exploit our music scene's "sarcastic emoticon" niche, at least until they have to look for a Plan B.