What you already know from instructional design and from web or e-learning development may also apply to mobile. However, additional attention should be made to:
- Length of content - short and to the point
- Consider utilization of some of the features of the mobile devices
- Consider easy navigation including bread crumbs or tabs
- Test on actual devices
- Use post-it notes or stencils for storyboarding
- Optimize the size of graphics for faster download
- Avoid background graphics
- Don’t include text within a graphic
- Pay attention to user interface, especially navigation
- Avoid using pop up windows, frames, tables and columns
- Do not requiring scrolling to the right; content should fit the screen dynamically
- Flash is not universally supported
- Plan to support HTML5 & CSS

The W3C has updated their Mobile Web Application Best Practices (W3C Working Draft 13 July 2010) - http://www.w3.org/TR/2010/WD-mwabp-20100713/