Cel Animation (Frame by frame):
As this movie demonstrates, cel animation (2D) begins with drawings of the characters and backgrounds. It is the drawing skill of the artists and producers that emulate the look of depth in the scene. This process uses drawings, cameras to capture cels or sheets of drawings, and an ink and paint process for colorization.
To create 2D animation using a computer many artists use Adobe Flash which is a 2D animation tool that also allows artist input either frame by frame or with computer 'tweening'. This page shows excellent examples of 2D animation using Flash. Click here
3D incorporates a workflow that goes like this:
Concept Sketches - Storyboards - Model - Shading/Lighting/Texture - Rigging - Animation - Rendering - Programming.
Familiarize yourself with the Blender education webpage (and the Blender site).
Complete exercises 2-6 on this Blender tutorial page