squared mugs

http://ceramicartsdaily.org/pottery-making-techniques/wheel-throwing-techniques/hip-to-be-square-making-squared-off-mugs-on-the-potters-wheel/

Cool video on altering pieces using the wheel, slabs, and coils. 

opening and throwing clay

Another link on getting started.  Remember, slow and steady hands on this.  Keep them in a tight position and move the clay.
http://www.youtube.com/watch?v=r3H89FEbqAk&feature=fvw

centering clay

http://www.youtube.com/watch?v=nsxgc5eKjrM&feature=related
A good video on centering clay, notice the hand position and movements.  Got to get centered before you can throw!!!