The Theme Chooser app makes changing themes extremely easy. A theme is normally based on a color and changes certain aspects of your device's appearance. Most themes will change the color of the icons on the notification bar and the color of some apps, but other themes will change a whole lot more.
To use the Theme Chooser app, first open the App Drawer from your home screen.
Scroll down to select Theme Chooser.
Slide through the themes until you find one that you like. Stop on it and click the "Apply" button.
Your device should now look a little different.
The Theme Chooser app comes with themes pre-installed, but if you would like to install more, follow these instructions:
-Open the App Drawer and choose Market/Play Store.
-Touch "Apps" on the left side of the screen toward the middle.
-Touch the magnifying glass in the top right corner and search for "cm7 theme" (if you're running Gingerbread) or "cm10 theme" (if you're running Jelly Bean).
-Scroll through to find a theme you want and click on it to read through the description and reviews. If you like it, press "Download."
-Touch "Accept and download." When the download finishes follow the steps above to set the theme