Start creating a circle using elliptical shape tool.

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

Enable "subtract from shape area" at the top bar. Create an ellipse using elliptical shape tool.

Create a small ellipse for the eye using elliptical shape tool. Apply same layer style.

Create a shape as shown using pen tool.

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

Create another small ellipse for the nose using elliptical shape tool.

From layer menu select layer style>>create layers. Select and merge all the resulting layers. Select eraser tool with soft brush settings and erase the right portion as shown.

Create lips using brush tool. Apply some outer glow.

Create some star shape using custom shape tool and apply some outer glow.

That's it.