Nice simple tutorial on how to build glossy / enamel type buttons.
Layer styles are effects built into the layer palette that enable you to work non-destructively. This means that the effects can be turned on and off, leaving the content of the layer unaffected. Layer styles are incredibly versatile, as this tutorial will hopefully demonstrate! The graphic shown below contains just two flat shape layers – all the effects (including the text on the badge) have been applied using Layer Styles.