Smartphone App User Interface - Lessons from Websites

Apps are relatively new compared to websites.  There's a lot of hard earned knowledge about website user interfaces. It might be useful to take some lessons from websites and apply them to apps. Here are a few starters:
At a glance understanding.
People skim computer based interfaces, they don't read them like you would a book. It's important to get people's attention and convey meaning quickly. Use elements such as images and symbols in addition to text.
Obvious navigation.  
People want to know where they are as they pass through an application. Give them hints about where they are and how to move around easily.
Appealing graphic design (colors, placement, font,...).  
People have visceral reactions to the look and feel of what they see on a screen. You may not be able to judge a book by it's cover, but if the cover isn't appealing, the content may never be seen.
Important elements above the fold.  
Don't make people scroll to see critical information. Put the important elements on the first part of the screen to appear.
Importance of names, symbols, etc.

Naming and creating symbols for your app, tabs, sections is important as an aid in remembering where users have been and where they want to go.