Figure out the simplest version possible and build it. If you can't do it yourself, set a budget to get a prototype made and test it out with a handful of users.
From experience: determine whether this idea will be a side project or a serious business. If it's the latter, you'll want to read up on running a software business (I'd recommend Starting & Sustaining by Garrett Dimon: http://startingandsustaining.com).
Figure out the simplest version possible and build it. If you can't do it yourself, set a budget to get a prototype made and test it out with a handful of users.
From experience: determine whether this idea will be a side project or a serious business. If it's the latter, you'll want to read up on running a software business (I'd recommend Starting & Sustaining by Garrett Dimon: http://startingandsustaining.com).