The layer’s parameters:
Fill 0%
Blending Options>Gradient Overlay
Gradient’s parameters: 
Take again the
Ellipse Tool (U) to draw a highlight on the sound’s regulator.
The layer’s parameters:
Fill 0%
Blending Options>Gradient Overlay 
Gradient’s parameters: 
Applying the
Rounded Rectangle Tool (U) with a radius of
15 px and white color, it is possible to draw a highlight on the player itself and on its buttons. But this layer should be positioned under the layers containing the screen and the play button.
The layer’s parameters:
Fill 10% 
Try to make now the central player’s button with the
Ellipse Tool (U).
The layer’s parameters:
Blending Options>Inner Glow 
Blending Options>Gradient Overlay
