A note on testing
As this chapter is about interaction and not just layout, it will help if you can test your work on a mobile device, particularly one with a touch screen. This will give you a much better feel for how easy it is to use the site on a mobile than if you were simply resizing your browser window or using an emulator on the desktop.
I will cover testing and the different tools you can use to do it in more detail in Chapter 10, Testing and Updating your Mobile Site, but in the meantime you might find it useful to beg, borrow, or steal (not really!) a touch screen phone unless you already have one.