John Lovett has a nice explanation with simple illustrations dealing with some key concepts here.
Wikipedia is a great place to start here.
*Digital web Magazine has some nice explanations here. really good examples here.
Design Principles: We want our compositions to have these qualities.
- Balance
- Proportion
- Rhythm
- Unity
- Dominance
Elements of design: We achieve the above principles using these elements.
- Line
- Shape
- Direction
- Texture
- Size
- Color
- Value
