The key to drawing cartoons is using basic geometric shapes, and exaggerating features. When starting out, it is usually best to practice one key feature first. Here I will show how to draw the head of a round-headed bear.
Time: 20 minutes
Draw a circle on a sheet of paper, then draw a curved vertical line down the middle to turn it dimension. You should also draw a curved vertical line at the back of the head as well, but these should be dashes to differentiate the space between the two.
Repeat this step, only this time draw the lines horizontally. The lines should be slightly below the halfway point. This should create the eye-line for your character.
Starting from the base line, draw two ovals for the eyes. The eye nearest you (in this case, the left) should be slightly larger to create the right perspective.
From the base of the eyes, draw a pear shaped muzzle that extends past the original circle, and draw 'squashed' circles on either side of the head for ears.
Create a heart shaped border around the eyes, and then a sideways heart to complete the face. Give your character a wide smile by drawing a line from one end of the muzzle to the other.
Draw an acorn shaped nose in the centre of the muzzle, then fill it in black, leave a white patch at the top to indicate lighting.