Moar sketching.
Warning, large images.
First, the finished version of the WIP I posted in the v5 thread. DPRK Propaganda.
http://dl.dropbox.com/u/7344169/DPRK%20Propaganda.JPG
Second, a portrait I did of my friend. She was always doing ones of others and wanted one finally done for her. CHALLENGE ACCEPTED. Just view it in a new tab so you can see the whole thing at once.
http://dl.dropbox.com/u/7344169/portraitedited.jpg
I know you didn't ask for c&c, but I reccomend some more in depth study into facial proportions if you plan to do more of that kind of thing because yours are a bit off. And you definitely need to make better use of values.