Step 1
Open a document and create a rectangle. Fill it with a bright color.
Step 2
Next use the rectangle marquee tool and select the top half of your rectangle. Create a new layer and fill this with any color.
Step 3
Double click this layer to goto its layer style. Apply a gradient overlay with similar colors. You generally want the same color on button and a lighter color on top.
Step 4
Now make a new layer and make a selection around the top of the button. Look at the picture for reference. Fill this with white. and change the opacity to 30%.
Step 5
Make a new layer and create another selection. Only select the middle of the block. Fill this area with any color.
Step 6
Double click this layer and apply another gradient overlay. This time you want the lighter color on bottom and the darker color on top. Now add whatever text you want and you're done.
Final Result:





More Photoshop: