S t e p   1

Create the shape and background color of the button or object.

S t e p   2

Select the background shape and shrink 1 pixel.   In a new layer add a gradient from the bottom up that fades from white to transparent.   Set the layer blending mode to "Overlay".   This adds the inner glow on the bottom of the object.

S t e p   3

Transform the selection to approximately half the height and bring in the ends some to make the shape of the glare on the glass.

S t e p   4

In a new layer, add a gradient from the top down that fades from white to transparent, extending a little bit beyond the selection so that some color will fill in the entire selection.

S t e p   5

Back on the background layer, chose Layer Style > Inner Glow and select a very dark color.   Set the blending mode for the Inner Glow to "Multiply".   Play with the opacity and size until you achieve desired results.   You may also prefer to use "Inner Shadow" instead, or in combination.

S t e p   6

To place text of an image 'inside' the button, you will want to place a new layer above the inner gradient from Step 2, but below the glare layer from Step 4.   A slight Drop Shadow and an opacity change make the finishing touches.

F i n a l   P r o d u c t

There are many other ways to achieve these results, and some others may even be preferable in certain circumstances; but the reason I chose this method is for its ease and flexibility.   Having the button background as an individual solid color makes it truly simple to change the color/hue/saturation of the button without compromising any of the other effects.