In case of making 2DCG using Blender, usually, using toon shader and edge function is normal way to do that.But this way needs to make a model, set a material and then render it. How do we make 2D more easily. This tutorial explains how to make a drawing type 2D.
(1) Select "Space Key" -> "Add" -> "Curve" -> "Bezier Curve".
(2) Make a shape you want using the bezier curve. There are two way to add more vertices(anchor). a) select a vertex located at edge and "Ctrl + Left button of mouse". b) select two vertexes which are adjacent and hit "W key" -> "Subdivide". You make the shape using these addition or add more bezier curve.

(3) Change "RenResolU" to 30 in the Curve and Surface panel. High number of this value makes the line smoother when the image is rendered. If you want to see smooth line during making in the 3D view, increase "DefResolU" above the RenResolU. "Bevel Depth" makes the line thicker.

When you finish making the shape, you need to change it to mesh. To do this, select the bezier curve in the object mode, and hit "Alt+C".
Select 「Material buttons」 in the button window, and hit the "Add New". Turn on "Shadeles" on the Material panel. And change its color(col) you want.

Change world color you want (this case is white as you can see), then render it. The result is below.

Turning on the "Wire", the line color becomes thickening.

This is a sample. You can make like this.

If you want to fill a color, you make a copy of this mesh. And fill with faces and color them.