UI design is one of those things that seems to alude many of us software developers (especially those of us that are the data-driven type). But, in my experience, UI design gets better...a lot better...with not just time, but a lot of practice.
A while back when I started to get into the visual aspect of software development, my WinForms applications looked hurrendous. Something straight out of the '90s. I got better at it, and before I knew it I picked up a few desktop/thick client design skills.
UI design is one of those things that just isn't boolean. There is such a gray area that nobody can really tell you how to do it and what is the way to go about it. You need to do it. You need to make some terrible looking applications. Then, and only then, will you know how to progress and what to change/modify/add/delete from your UI toolbox.