Coming to your site, it was pretty clear how I could interact with the site, but not why I should bother. It might be obvious to you, since you've worked on it, but it's not to a casual browser. Compare to https://www.gotinder.com/ which works hard to clearly sell the benefit of the service.
One suggestion I have is to interface the app with Facebook and/or Twitter accounts. For example, once you take and post a selfie in the app, it can post a message on your Facebook/Twitter profile letting that user's friend's know that, not only can they rate their friend's attire, but also help spread the word of your app.
If you already have this feature, you should definitely display it on your site.
I'm not so sure I agree with the approach of treating your users as somebody that has the attention span of 2 seconds and after that mindlessly wanders off somewhere else, but that seems to be the general advice.
Personally, I wouldn't download a style app that wasn't itself stylish. It'd be hard to recommend to my stylish friends. And something like this will take off via word of mouth and community building.
Right now, afaik, the leader in this space is Pinterest. You could do the same sort of thing Instagram did to Facebook--be the indie alternative that the cool kids use. But IMO you need more of that cool kid mojo. I'm not quite sure how to get it... brilliant designers and product people are hard to find. Maybe you are brilliant, but haven't put enough time and polish into the product yet.