This instructable will demonstrate how to construct a head out of clay. It is a very easy method which provides a realistic result. As a bonus, it is always looking at you, similar to the effect of the "Mona Lisa" except it uses a concave-convex illusion. I hope you enjoy this and create many sculptures. Feel free to add onto these ideas to create your own artwork.
I realize that the number of steps in this instructable is rather large, but each step is quite quick. You will be able to finish them faster than you might think.
A tip that I have for you is that you should not rush, concentrate on what you have to do on each step and try to follow as best as possible. Each head will turn out different. If it seems that it will become a sad face, let it become a sad face, if it seems that it will become a laughing face, let it become a laughing face. Don't get discouraged if it does not come out exactly as I did mine or as you expected it to be. Trying to change it will most likely ruin the sculpture.
It is very easily done with common household supplies. The supplies that you will need are a pair of scissors, a blob of clay, a paperclip, a Popsicle stick, a straw (optional), and a length of string that is about 2 feet long (optional).
Please follow this instructable and please, HAVE FUN DOING IT!

Step 1: Your Supplies

As mentioned before, these are all of the supplies you'll need. You will need the clay to make the head and a base for the head, the Popsicle stick and the paper clip for detailed features, the straw for making a hole in the head if you wanted to make it a bead, scissors for cutting the string, and the string for making a necklace out of the bead.

Step 2: Shaping the Ball of Clay

Separate a piece of clay that is about the size of the circle created with your pointer finger and thumb. Roll this into a tight and smooth ball. Then, shape it so it is a bit oblong like an egg (make sure it doesn't come out like a cylinder because that will distort the face and make some steps very difficult).

Step 3: The First Impressions

Take your Popsicle stick and press it into the clay twice to create the eyes and press once for the mouth. IT WILL END UP LOOKING LIKE AN ALIEN! Try to keep it the same as in the pictures. This part is essential for fine details later on. You start with the coarse details and end up with the fine ones. Do not press too hard nor too softly. Practice is what makes each head better. You may notice that in the fourth picture in this step, it looks vaguely that there is a nose there but from the side it looks flat. The next step involves making that nose look like a nose from all directions (except the nostrils which will come into play when we do the finer details).

Step 4: Picking the Nose :P

We now need to take the spot where the nose should be and squeeze the sides together so it pops out. BE VERY CAREFUL to not let it get too thin or it may crack or get accidentally destroyed. Shape it a little bit so you like how it looks.

Step 5: The Neck and the Chin

In this step, we will be creating a neck and a chin to go along with our head. It is very important not to make the chin too close to the bottom of the nose because there will be no room for the mouth and the bottom lip. The way you create the chin and neck are all in two moves. The first one is pushing the bottom sides together to make the neck and the second is to push down the bottom front to create the chin. If this all makes sense to you, you should get it right. It takes a lot of practice and is hard to explain in words.

note: the neck should be around the same width of the head, not thin.

Step 6: Mouth and Lower Lip

This step is where we will be sculpting the mouth and lower lip (YAY!). Take your Popsicle stick and use the tip to create a deep horizontal impression where the mouth should be. remove the Popsicle stick carefully. Now, you need to create the lower lip. You now need to place the tip of the Popsicle stick onto the chin so it is resting there and push it forward so the bottom lip almost touches the top lip without disturbing the chin.

Step 7: 'eye'-'eye'

Create impressions the same way you did to make the mouth, but in the eye sockets. Make sure that one is not lower than the other. Next, take your paper clip, unfold it partially, and poke holes in the center of the eyes for pupils. If you rotate the head, the eyes follow. I find that pretty neat.

Step 8: The Fine Finishings

Take the Popsicle stick and smooth out any rough parts to make it look more realistic. Take the paper clip and VERY carefully poke holes underneath the nose to create nostrils. The ones I did were little off center and a bit too small. Try to make it a realistic size and symmetrical.

Step 9: EXTRAS

Here I have provided two ideas of what you can do with these heads. One is to stack them on top of a hunk of clay with one, two, or maybe even more of these heads. Another is a bit more complicated. Take the head and push a straw through the side with a twisting motion and let it come out the other side. If the face becomes distorted, VERY CAREFULLY squeeze it back to place. Cut an acceptable length of string and thread it through the head. Tie a knot on the string and wear it as a necklace.