We have all seen them-beautifully modeled and textured characters that have no depth. They look like little actions figures. Which don't get me wrong, action figures are cool. But they are posed with one expression and generally one body pose.
Which might be totally awesome for that one instance it was designed for, but does little for further exploration of a character or storyline. In order to connect with a character, the viewer needs to see that the character actually has a full range of emotions.
Of course the best way to show this is through well thought out facial expressions that can be easily read. But even great facial expressions by themselves aren't going to do it. The facial expression needs to reflect the body language and what is actually going on in the scene. Nothing is more confus-ing for a viewer than a character bouncing around like a happy kid in a candy store with a sad, woe begone facial expression, in a scene that doesn't call for either.
Now, obviously that was a very silly example, but it does illustrate the point that facial expressions and body language actually need to reflect what is hap-pening to the character in the scene.
Just how do we go about creating believable facial expressionsí Well, having a limited budget, I usually turn to the Internet when I want to know something. It is absolutely amazing what you can find.
While buzzing around online (something I do far too much of), I ran across a very cool blogrun by Dani Jones. Oddly enough, the link I followed dropped me right on the best post ever, 50 Facial Expressions and How to Draw Them. Now granted, he is a traditional illustrator and we work in 3d. But the knowledge he shared in this post transfers beautifully from 2d to 3d. I encourage you to go chek out his blog (http://danidraws.com/blog/).
In the meantime, here are some important tips he posted about facial expressions:

The Most Important Features

1.The Eyes – Probably the most important feature for evoking a clear emotion. Utilize the eyelids and eyebrows to create your effect.
2.The Cheeks – The way they squash and stretch will affect the look and position of the eyes.
3.The Mouth – The shape of the mouth is alos very important. It affects how the cheeks move and the shape of the entire face.

Additional Tips

Note that when you move the shape and position of one feature, it affects everything else. Nothing stands completely on its own.
For a stronger drawing and character, really push the expression. Instead of simply drawing a happy person, draw one that is ecstatic; instead of drawing an angry person, draw a furious one.
Have a mirror nearby. When I’m trying to nail down an expression, I often find my own face making weird movements unconsciously. It can make for good reference.
In addition to the above tips, Dani Jones alos had a Facial Expressions Chart of 50 different facial expressions for you to study and a pdf for download. Some of the expressions are just priceless and are well worth check-ing out.
Now you have some nice facial expression reference, what nextí Well there is no one better to consult than the masters. Further exploration led me to http://www.frankanollie.com, online home of Frank
Thomas & Ollie Johnston. They have a great page on their site (actually their whole site is filled with great information) that discusses emotion in animation. They developed a list of 12 questions that you should asque yourself when animating your characters.

Keys to Emotion in Animation

by Frank Thomas & Ollie Johnston, June 2003
1 Is the character doing what the director wants in the sequence?
2 Is the character doing only one thing at a time?
3 Is the character putting over the story point in the scene you are doing?
4 Is the character acting as if there is something going on in his mind?
5 Does the character appear to be doing something on his own?
6 Can the audience tell what the character is think-ing?
7 How does what the character is doing effect what the audience is thinking?
8 Does the character have appeal?
9 Is it passionate? Is passion going into the drawing and coming out of the character?
10 Is it the simplest way to do ití
11 Have you made small story sketches of one im-portant character to be sure everything is work-ing before you make a lot of drawingsí
12 Would any one else besides your mother like what you have done?
Now we have a bit of reference and direction, and it is time for the Blender component. How do we get those wonderful expressionsí Of course there is not just one way to do anything in Blender so here is a list of video tutorials that cover various techniques you can use to create and animate facial features.
Rigging a Pupil for Dilation Creating a Face Rig Learning Action Constraints Time to practice, practice, practice. Remember to look in a mirror often and watch your own face, get your buddies to make faces for you as well. In no time you will be creating an expressive range of emotions