Drawing people

I have a hard time drawing people. In fact I tend to avoid them when I sketch.  So I tried practicing by looking at a photo of these Chinese Opera actors.  The photo was taken by Tia an urban sketcher from Singapore.  Check out her flickr site for the real thing.  http://www.flickr.com/photos/tia_studio/4953705988/in/photostream/
Here is my sketch rendition of the photo.