These Tutorials are more for drawing realistic styles/illustrations
but i think basics are still important regardless which style we pick
[Prometheus Spawning Grounds ]
http://itchstudios.com/psg/-go to the tutorial section and it has the basics of lighting,shape and form
[FURIAE]
http://www.furiae.com/-Useful tutorials on how to paint the eyes, noses and hair on the tutorial section
[The art of Steven stahlberg ]
http://www.androidblues.com/-Useful Cloud tutorial and painting tutorial on the tutorial section