1. Open a new image and fill it with your paper color.

2. Select your eraser tool. From the brush menu, select a round brush and make it small. I used the following settings for this tutorial:

3. With your eraser, make a jagged line across your image, where you want your paper to look torn. Erase everything above your line.

4. To add a white edge to your tear, select the Dodge tool.

For this sample, I used the following settings:

5. With a jagged hand, draw your torn edge at the tip of your paper. This simply lightens the image. Release the mouse and do it again. This will lighten the new area you've already lightened. You can release the mouse and go over areas to give a more torn look, or leave it as is for a lighter tear.

6. The basics are now complete. You might add shadows to make the torn paper pop off the page, or add noise for a more realistic looking paper. Play with the settings until you get a look you like.