This article was written by a guy who created his web app without knowing Rails. In a few months, he had learned Rails, and had designed, developed and launched his own app. So don't be discouraged!

There's so many wonderful resources out there on UI/app development, but what I got from this article is that these lessons you'll learn best by creating (and using) web apps.

Here's the author's Rails article on the same site: http://sixrevisions.com/web-development/why-making-web-apps-...