To think about design, you need a vocabulary to describe the object. This needs to be combined with a structure of principles. What follows is an outline to structure your thinking about design. This is based on the writing of Burton Wasserman in Spark the Creative Flame, Making the Journey from Craft to Art, by Paul J Stankard, 2013.
First there is the vocabulary to structure the conversation about design. The elements of this are “… point, line, plane, texture, colour, pattern, density, interval, … space, … light, mass, and volume”
There are then principles of good design. They relate to:
Unity – all the elements form a whole
Balance – note, not only symmetry
Rhythm – this can be repetition with or without variation
Emphasis – or contrast between a main element and the rest
Harmony – all the elements work together
These five principles of design together with the vocabulary of elements form the language of design and assist your critical thinking about expressing your design and realising it in the best way you can. This thinking can be applied usefully to the critical appreciation of others’ works.