UX touches every aspect of a project: the design, the layout, the usability, the million little things you forget about...like the speed at which it loads and the feeling it leaves users with.
Like Jobs said "Design is not just what it looks like and feels like. Design is how it works."
Good UX starts early, in the planning phase. I've been in plenty of situations where we have to work with a certain layout because "it's already built that way." I can roll with that, but it's clunky. On the other hand, I've got enough startup experience to understand the MVP (minimal viable product) approach and the need to get something out the door. The need to iterate frequently. The right approach depends on project goals...and a commitment to never make something you'd be embarrassed to show your Mom (well, my mom...she's quite good).
It's no longer hyperbole: the publishing ship is sinking. It's tough. Exciting. There is opportunity in chaos! I've launched 2 publishing startups that focus on social features inside books. I've also worked on an iPad reading system, an EPUB conversion service, a library-social network startup, a location-based storytelling app, an audiobook rights and recording exchange, a service that ties commenting on Google books to Facebook groups, a code snippet that lets you skin iBooks, and digital galley service. Every project requires a knowledge of both publishing and the web; they always draw heavily on my UX and Creative Direction experience.
Creative Direction is important - the buck needs to stop somewhere (I'm okay with it being with me). Here are a few rules of thumb. First, orient yourself to what you're building. Tablets aren't like phones, they're held and used differently. The web is another beast entirely - you can get people to wait longer but can you get them to come back? Next, find people you trust, people who want to work with you (that's pretty important, actually), and get cranking. UI, development timelines, APIs, and design conventions depend on who the user is and what they're trying to do. I don't know how to do everything (shhh...don't tell anyone), but I know who to ask and how to figure it out, which is really what innovation is all about.