Add the layer style we applied to the Interface layer in step 5.

Then add some Drop Shadow - default settings - but change the Distance to 2 pixels and Size to 2 pixels.

Duplicate the Button layer by dragging it down to the Create a new layer tab. Do this until you have the buttons you want and nudge them into the right positions.

Then link all the different button layers together and hit Ctrl + E to Merge the linked layers together. Rename the layer and call it Buttons.

Then add some Drop Shadow - default settings - but change the Distance to 1 pixel, and the Size to 1 pixel.

Create a new layer below the Buttons layer and call this layer Inset Buttons.

Press Ctrl + left click the Buttons layer to select the buttons.
Now get rid of the lower selections of the buttons so that only the top buttons are selected.

Do this by first clicking the Subtract from selection option an then selecting the lower part of the buttons selection.
Your image should now look exactly like fig. 23!

Then go to Select - Modify - Expand - 2 pixels.
Hit D to set the Default colors (Black foreground color and white background color)
Select the Gradient Tool And fill your selection from the top to the bottom. Deselect.

Now duplicate this layer and move it down beneath the lower set of buttons.

Your image should now look like figure 24.

Link the two Inset buttons layers together and Merge the linked layers together.

Then run a Gaussian Blur - 4 pixels.

Now it's time to add some details to some of our layers.

Activate the Chrome Detail and duplicate it.
Make a selection similar to mine in figure 25 and inverse the selection (Ctrl + Shift + I).
Hit the Delete key. Deselect.

Then turn off the Drop Shadow layer style !

Then go to Filter - Blur - Gaussian Blur - 5 pixels.

Still at the Chrome detail copy layer select the Chrome Detail layer (Ctrl + left click the Chrome detail layer).
Inverse the selection and hit the Delete key (make sure you are on the Chrome detail copy layer) to get rid of the pixels outside the selection. Deselect.

Duplicate the Chrome detail copy layer and go to Edit - Transform - Flip horizontal - and move the layer to the right side.

Your image should now look like fig. 26.

Activate the Background Buttons layer.
Create a new layer called Highlights.

Select the Elliptical Marquee Tool and make a selection similar to mine in figure 27 and fill the selection with white.

Then move the selection using the arrow keys until it looks exactly like fig. 27.

Hit the Delete key to get rid off the selected area.

Now duplicate the Highlights layer 3 times and use the Edit - transform - Flip Horizontal/Vertical option and move the different highlight layers until it look like figure 28.

Link the four different highlights layers together and Merge the linked layer together (Ctrl + E).

Then go to Filter - Blur - Gaussian blur - 3 pixels.

Create a new layer - call it Highlights 2.

Make a selection similar to mine in fig. 29 and fill the selection with white color. Deselect.

Gaussian Blur the layer - 2 pixels

Duplicate the Highlights 2 layer and move it down below the lower buttons.

Then use the Eraser Tool to get rid of the center of the layer like shown in figure 30.

This is the settings I used for the brush I used to erase some of the layer.

Create a new layer and call it Black Shadow.
Make a selection similar to mine in figure 30 and fill it with black.
Then Gaussian Blur the layer by 4 pixels.

Now duplicate this layer and move the Black Shadow copy layer over to the right side.

Ahhhh - finally there!!!

Just add some Pushed in text on top of the buttons and you're finished!

This tutorial could go on and on for ever, but I'll stop here.
Use your imagination to add even more cool effects to the interface :)

Good luck!

(Click here to see my very final result that I have entered in the Eyeball interface contest).