Drawing a cool cartoon sun

Start by select polygon shape tool. From options bar at the top choose settings as shown below.

Press Shift while creating this shape to get equal axes.

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

Create a circle using elliptical shape tool. Apply gradient overlay layer style as shown below.

Create an ellipse using elliptical shape tool.

Enable add to shape area from the top bar. Create another ellipse using elliptical shape tool. Using line tool create a line connecting both glasses.

Apply a gradient overlay layer style.

Using pen tool create smiling lips as shown below.

Also create eyebrows slightly above the glasses using pen tool.