As with any project, it is important to have a plan before you attack an illustration. Below is an example of how simple a presketch can be. Even though a five minute doodle looks crude and uninspiring, it is still a good foundation to build your ideas off of.

It is important to understand the effects of facial expressions on characters. The face is what will tie everything in your artwork together. Usually in my work, I start with the face first so that in the end I won't have to worry about what my character will end up looking like. Development of themes are easier also when you have an expression to base your design off of. Below is a few sketches of a simple character showing several different emotions.

Using the premade shapes in Photoshop or Illustrator's tool bar can be a great way to start off. Also, try thinking of how basic geometric shapes such as circles, squares and triangles make up objects in everyday life.

If you're having trouble using the pen tool to create shapes on a white canvas, scanning and tracing your old sketches and drawings is a great way to have guidelines. Simply use your trusty scanner, or have a friend scan it for you, and either use the pen tool or free from pen tool to start illustrating!