First make new document, any size you want. Make new layer and name it button. Use rounded rectangle tool to create the shape for button like this on the picture bellow, set radius to 4px.

Now go to layer style window by double clicking the layer and use these settings.

The button will look a lot nicer now. All you have to do now is to add glass effect and text. Create a new layer, name it “glass” and put it on top of the button layer. Make a selection as in the picture.

Then hold CTRL + SHIFT + ALT and click on the button layer. This will create next selection which will be used for glass effect.

Select the glass layer and fill it with white color. Put the opacity of this layer to about 20%. Add some text and you’ll get vista button.