In this tutorial I'll show you how to create and save your own Keynote and Pages themes.
In order to create your own theme in Pages or Keynote, you first need to choose an existing theme. Once you have done so, you can move on to customizing your theme by editing the master slide templates. After you have done so, simply select: File > Save As Template/Theme > Add to Template/Theme Chooser. Lastly, provide a name for your theme or template.
Your new template/theme will now appear in the "My Templates" tab in the Pages sidebar and the "My Themes" tab in Keynote.