Theme usability design guidelines
Themes and Usability
Creating user-friendly themes is quite straightforward if you keep the following things in your mind:
Style:A theme is more than a background image - a theme should have a unifying idea with a consistent style and balanced colour palette.
Contrast:Mobile devices are small and the text and icons on them are even smaller - a good contrast should be provided throughout the theme, so that the icons, texts, and the focus and scrolling indicators are easy to interpret. Even the best sketches need revising and require hard-disciplined work to make them really good.
Theme Components with high Usability
The idle background is displayed when the device is in idle mode and it can be practically anything you like or think the users of your Theme would like.
Note: There will be things on top of the idle background that have to be readable, such as the date and the time.