Designing Vesper to guide the users

How can app design can steer users to using apps in a certain way? A nice write up from the designers of Vesper, a minimalist note taking app for the iPhone:

If you’re really good at what you do, it looks easy. But easy is tough to sell to clients, so we designers develop bad habits in order to make our work look impressive. Early on with Vesper, we realized that the existing design was okay, but felt cheap, like it was built using the same visual tricks everyone uses to make something look designed. As it happened, we were all heavily addicted to Letterpress, and we wondered aloud if that visual style might be where the puck was headed. If so, what would that mean for UI in general? The only way to pull it off well — and a good idea for us at this stage anyway — was to strip away everything and add back only the pieces that we needed.