You have gotta think about perspective more with planes. Try conte's planes exercise: http://dl.dropbox.com/u/2491209/tutorials/constructpracticetutorial.jpg http://dl.dropbox.com/u/2491209/tutorials/constructpracticetutorial2.jpg (from his sketchbook)
If my sketchbook pics dont work at the moment its because my dropbox is down for a few days :( 1 hour 30mins face study from a sphere; Also made a weapon texture tutorial for some friends this week, decided to share it, here is the thread: http://www.polycount.com/forum/showthread.php?t=93799