Most of the times the default templates used for apps have very basic color themes: black and white (okay, and some gray). Your app will come more to life if you use a good color theme, matching your content. Question is: which colors are best to use?
Select a color theme
Something I found very handy is the website http://kuler.adobe.com. This website offers a large collection of color themes, where each theme has 5 colors. You can search for a topic to find interesting themes, e.g. ‘vacation’, ‘beach’, etcetera. This is an example of one of the themes:
These colors are then the basic colors of your app. There is not a real default selection which color is used for what. You have to make your own choices there. Just make sure that the contrast always works. E.g. dark text on a light background is most of the time best for reading.
Whit Kuler you can see the RGB values of the colors by clicking on the button just before News & Features on the right.
This can be useful to enter them by hand in Blend or Visual Studio. You can also “copy” them by using the eyedropper tool either in a design tool like Photoshop or Blend. In the picture below you see the color editor in Blend (usually on the right). The light green circle shows the eyedropper tool. Click the tool and then click the color you want to “copy”. The light blue box marks the color edit box. In that text field you can enter the HEX value that is shown above in Kuler.
Using the color theme in a structured way in your app will bring your app even more to life.