Use your little finger or your favorite tool to flatten a bit the eyes area
With the Xacto knife, trace a line for the mouth
with a flat or round tool, make a little mark for the bottom lip
then mark each end of the mouth
then form the bottom lip, gently
then push the clay gently up the upper lip to form the nose
then push gently on each side of the nose, like a triangle
make sure your mouth is well defined - if not, mark each side again
if you want a pout, just push the upper lip up with your blade
then go on with the rest of the face! Easy, uh? :) Hope it helps!