Aesthetics is innately subjective, i.e. “Beauty lies in the beholder’s eyes.” In design, this subjectivity challenges the designer to build the aesthetic value of the artefact, while not compromising its functionality or usability. Such design with constraints presented by predefined forms is typical in architecture and industrial design, where “form follows function.” The user and designer here lie at opposite ends of the spectrum of visual interaction with the artefact. The present study aims to empirically understand the basic construct of the aesthetic value of any physical artefact, in design. In addition to objectively reasoning the aesthetic phenomenon, it also establishes guidelines to optimise it in any composition. For this, 2D rectilinear planes were chosen as the basic elements of design. Fifteen three-dimensional foam board sketches were constructed with the same five rectilinear planes of different proportions. Their organisational structure was investigated with 2D elemental sketches that analysed the underlying abstract principles of design within the composition, namely—balance, proportion, unity, variety, emphasis, contrast, rhythm, movement, harmony, and hierarchy. Further analysis across compositions revealed the effect of weight, orientation, clarity, and overall proportion of the visual space, viz., aesthetic indicators—Effect-to-Effort Index, EEI; Visual Clarity Index, VCI; Visual Skewness Index, VSI—that were developed to define aesthetic value. As a result, a set of optimisation guidelines for the aesthetic design of an artefact was formulated.