Ruth Padel

• Symmetry

Increasing an element's scale in a design piece increases its value in terms of hierarchy and makes it to be seen first compared to other elements while decreasing an element's scale reduces its value.

• Composition (visual arts)
• Gestalt laws of grouping
• Interior design
• Landscape design
• Pattern language
• Elements of art
• Principles of art
• Color theory

• Kilmer, R., & Kilmer, W. O. (1992). Designing Interiors. Orland, FL: Holt, Rinehart and Winston, Inc. ISBN 978-0-03-032233-4.
• Nielson, K. J., & Taylor, D. A. (2002). Interiors: An Introduction. New York: McGraw-Hill Companies, Inc. ISBN 978-0-07-296520-9
• Pile, J.F. (1995; fourth edition, 2007). Interior Design. New York: Harry N. Abrams, Inc. ISBN 978-0-13-232103-7
• Sully, Anthony (2012). Interior Design: Theory and Process. London: Bloomsbury. ISBN 978-1-4081-5202-7.

• Art, Design, and Visual Thinking. An online, interactive textbook by Charlotte Jirousek at Cornell University.
• The 6 Principles of Design