One way I like to sketch faces is while I watch TV. I just use some copy paper and a pencil. No pressure! I pay attention to the facial features of the characters as they are on the screen and quickly sketch. It is a fun way to draw quick little studies of the human face and explore all the beautiful differences each of us have.
The scribbly mess in the upper right hand corner is my warm up. Then I moved on to the complete face below it. Then I just started drawing random features all over.
Something about how this jumbled mess ended up makes me happy! Now that I have scanned this image I can print it out with my laser printer and include it in some way in my art journal. Maybe even add some color. The options are endless and it'll be fun to experiment!