Start by tracing your outlines with the Spline tool in the FRONT view.
Then go in the left view and move vertices around to get a 3 dimensional basic outline.
Use Shapes (like a sphere for the eye) to help you follow a curve.
This step only can take you a LONG while if you want to do it right.
Once you have the basic outline, follow the contours of the eyes and mouth to fill the empty spaces (follow the muscles, radial from the mouth if you want to animate your mouth later on)
There's no perfect way for a spline, try to keep it simple and make sure you only have 3 or 4 vertices per face, to use Surface Modifier.
Once you have the surface created you can apply your texture.
Then the spline work can be converted into a mesh
Using the Morpher modifier you can create several key poses and use them in your animation
