Add a layer above that and use the paintbrush (size of 1) and about #E7E1DD to paint some teeth.
Add a new layer and use the paintbrush at a size of about 4 and #F7E5D7 to paint some highlights on his nose and cheeks. Use a gaussian blur of about 3 for this.
Add a new layer, change your foreground color to null and your background color to white, use preset shapes teardrop to make some eyes.
Use the same drop shadow on this layer, changing the color to black and the blur to about 7.
Then I used the paintbrush at a size of 1 and black to paint some little lashes on a new layer, turning the opacity of the layer down a little.
Add a new layer and use preset shapes ellipse, fill color of black, to make the inside of the eyes.
And then use the paintbrush at a size of 1 and #787C96 to paint some blue in his eyes on a new layer, give this a blur of about .65
Use white to add two little highlights in his eyes on a new layer.
Make the boys pants your active layer, use the retouch tool 
with the settings below to highlight around the top of the pants.
Add a layer and use the paintbrush at a size of about 12 and #424554 to paint some shading on his pants, then use a gaussian blur of about 6 and clear around the edges.
Change your brush size to 2 and use the same color to add more details to the pants on a new layer. Use a gaussian blur of about 1 or 2.
Now I added a layer above that and used a button tube for his pants.
Make one of his legs your active layer and use the paintbrush (size about 10) and #9C875C for shading, using a guassian blur of about 4 and clear around the outside.
Then change your brush size to 1 and use the same color to add some lines on a new layer, using a blur of about 1 or 2 and clear the outside.
