Start out by drawing a rounded rectangle that looks similar to the image below (roundness = 20-30%).
For a later step, duplicate this layer 2 times (CTRL + C then CTRL + V) X2. Hide the 2 duplicate layers and use the visible layer for the next few steps. (Also, make sure that your duplicate layers have no Stroke Color.)
With your visible rectangle selected, set the Fill Color to a light gray (#EBEBEB), and set the Stroke Color to a dark gray (#939393).
With your rectangle still selected, go to the Properties Inspector and click on the + icon in the Filters section. Choose Shadow and Glow | Inner Shadow, and set the options exactly like the screen shot below.
With your rectangle still selected, go to the Properties Inspector and click on the + icon in the Filters section. Choose Shadow and Glow | Drop Shadow, and set the options exactly like the screen shot below.
Un-hide one of the duplicate layers from step 1 and drag it to the top of all of the layers in the Layer Pallete.
With this new rectangle selected, go to the Properties Inspector and set the roundness to 100%.
With the 100% round rectangle selected, move it up so that the bottom of the rectangle is located at the mid-point of your 30% round rectangle. Take a look at the screenshot below to see what I’m talking about.
Now for the hard part. Un-hide the 2nd duplicate layer and drag the layer to the 2nd from the top of the other layers in the Layer Pallete. Your layer order should now be:
- Top Layer = 100% round
- Middle Layer = 2nd Duplicate
- Bottom Layer = 30% round with Live Filters
Hold down the Shift Key and click on the Top and Middle layers in the Layer Pallete so that both layers are selected.
Go to Modify | Combine Paths | Intersect. Your middle layer should now be gone and the top layer should look like the screenshot below. (I set my layer to a dark gray so that you can see it better).
Select the top layer (the one that looks like half of a rounded rectangle) and move it down 1-2 pixels(whatever looks good) on your canvas.
With this layer still selected, set the Fill Color to white (#FFFFFF) and set the opacity to 65%.
Your image should look the one below.
To get an even more authentic look, add some Helvetica/Lucida Grande text above all of the other layers. Add a slight drop shadow to the text and you will have a super realistic Aqua v.2 button.