In this lesson I'll teach you how to represent a RSS button. Firstly we need to create a new file (
File>New) of
512x512 px and
72 dpi. Place there a rectangle that may be made with the
Rounded Rectangle Tool (U) (radius of 25px) 
The rectangle should have the next indicated
Blending Options>Gradient Overlay parameters by making a mouse click on this layer on the layers' panel.
Gradient Editor

You'll get the next picture:

Then we have to make another rectangle that will be placed the same way as below:

Set next demonstrated
Blending Options>Color Overlay.
Gradient Editor
Blending Options>Stroke
Gradient Editor
We'll get the next picture:

Now we have to represent one more rectangle near the previous made one.

Do the same operation we did with the previous rectangles:
Blending Options>Gradient Overlay
Gradient
Blending Options>Stroke
Gradient