The demand for creativity is a significant concern in all educational environments, especially in institutions of design. Considering this, the study aspires to improve creativity in the design studio. Based on the theories and research addressing creativity in the design field, creative decision-making, and cognitive processes during creative activity, this study analyzes the creative process of design in depth by investigating the characteristics of the decisions made through the stages of the process, and means of supporting those decisions for the main purpose of enhancing academic and professional creativity. The study establishes its basic framework by combining two different models: ‘4P’s’ of creativity by Rhodes and the ‘Five Stages of the Sensational Thinking Model’ of O’Neill and Shallross (5R’s), and makes use of the methods of protocol analysis, observation, product assessment, and retrospective interviews. Implemented in the third year design studio in the Interior Architecture and Environmental Design Department, Bilkent University in Turkey, the study yielded significant results on preferred imagery and representation styles and quantity, time spent at different stages of the process, underdeveloped skills, behavior, in addition to student-student and student-instructor relations, and associations between creative processes and products. Moreover, constructive interaction between students was observed to be helpful in developing their ideas, and students who have used more imagery were detected as more creative. A model was proposed to understand the creative process and test the hypotheses, refined according to the study, and presented in a way to be readily utilized or adapted to various situations.