Create a rounded rectangle for the eye using rounded rectangle shape tool.



Press Ctrl+T. Right click the layer and select warp. Adjust nodes to get the shape as shown.



Apply same layer style that we used for the face. With gradient overlay panel open drag the gradient slightly downwards.



Ctrl+Click the layer thumbnail to get the selection. From select menu apply modify>>contract. Contract the selection by 2 pixels. Create a new layer and apply a black to white gradient in linear mode.



Change the layer mode to screen.



Select eye layers. Duplicate. Press Ctrl+T. Right click the layer and select flip horizontal to create the other eye.



Create lips of the smiley using pen tool. Draw it bent downwards to create a laid back expression.



Double click the layer to open layer style window. Apply layer style with the settings shown.