Photoshop: how to create buttons that look "subtly pushed"?

Any ideas how can I create "subtly pushed" buttons like the "Active filter" buttons in the following screenshot?

The mockup is from here.

UPDATE: Here's what I have got so far:

Answer

Try using an Inner Shadow Layer Style:

You can tweak the size and opacity to adjust how subtle you want the effect to be

Edit-- How to closely replicate the example:

Taking a very close look at the example, it "pops out" using 3 features:

1. An inner shadow to give the button depth


2. A white drop shadow to give the foreground depth


3. A gradient stroke to give the button more depth

I used the following layer style settings to try and recreate the example as close as possible (in addition to a Gradient Overlay of course):

The Result: