Put elements in opposition to each other by their colour, shape, texture, material or scale.

This design principle can be achieved in different ways:

• Pairing light with dark colours
• Small elements with large elements
• Textured with non-textured surfaces

High contrast can be achieved through the colour and texture of pillows, light colour from the walls with a dark colour of the furniture, or transparent objects with solid ones. 

Rhythm in design is about creating patterns of repetition and contrast to create visual interest and flow, which moves the viewer's eyes around the space.

The design is tied together by duplicating elements, colours, shapes or patterns. For example, you can establish a rhythm by using a colour in the pillows,  picking it up in a painting, and again in a rug. 

Balance is about equalizing the visual weight of objects. Balance creates a feeling of equilibrium, stability and unity.

• Traditional or formal spaces need symmetrical balance. The space is evenly split into two sides that mirror each other.
• In asymmetrical balance, the visual weights of lines, colours, forms, and textures are balanced without exact duplication. 

• Scale relates to the size of objects within a space.
• Proportion is about the relationship between two elements. It's how the object relates to the overall context.

An example of a wrong proportion is if you have a large sofa and place a small side table next to it. 

Harmony is created when all the elements act together to create a unified composition. They may fit the same theme, aesthetic style or mood.  Each piece seems to belong together in some way, even if it is not identical to anything else.

To create unity and harmony in your space, define an aesthetic style. This way, you have parameters of colours, textures, and shapes to create a cohesive atmosphere.