It's hard to vet non technical co-founders. Really hard. Unlike developers they can't always (though sometimes can) show you, "here's what I did." They don't benefit from the same kinda portfolio like a designer/artist or developer.

That said, you could go to meetups in your area (if there are any). Network a bit. You gotta put yourself out there and you can't be afraid to talk about your idea. You might even find someone else with the same idea.

More importantly, figure out what you need a co-founder for. It'll be easier to find one then. You'll know what questions to ask and what to look for. Are they helping you find finding? Find customers? Market the idea?

As far as how you do it alone? Self-education. Both programming and design lend themselves well to self-education. Marketing does as well. Especially these days with the internet and social media. You don't necessarily need an MBA, but if you can pick up just a tiny bit of the skills you need to market and push an idea out there, you're going to run into someone to be your business co-founder a whole lot easier. You'll also better be able to evaluate them.