I Can Has Outline Text
One of the three ways to make text clearly visible on an image is to outline it in a contrasting color.
An example of this would be an I Can Haz Cheezburger picture. Let's make one for fun:
1. Search for a cute animal picture on Google Images.
2. Open it in Photoshop.
3. Click the text tool (looks like a T).
4. Change the text color to white if it isn't already--click the colored box in the toolbar at the top of the screen.
5. Type something on the image. The name of the font that everybody uses for this meme is Impact.
6. Create a black outline for the text by clicking Layer -->Layer Style -->Stroke. Set it like the screenshot below. Save the picture when you're done.