At a time when concept driven competencies are perceived to be critical in redefining effective technological education, the introduction of Design and Communication Graphics at senior cycle in Irish high schools has broad implications. Students now have the potential to explore applied geometries, integrated with conceptual thinking in addition to developing essential communication skills. As a result, freehand sketching has become an integral facet of all technological subjects. Action research currently being carried out at the University of Limerick aims to identify a sustainable intervention strategy for the development of concept driven competencies in students of technological education. Core to this is the development of students' ability to freehand sketch what is both perceived and conceptualised. This paper presents findings of an intervention strategy carried out with a cohort of 124 pre-service teachers of technology education. The study develops participant's ability to engage in higher order symphonic cognition as well as the harmonisation of fundamental communication skills through the medium of freehand sketching. The approach for the research followed a five phase intervention strategy. An initial pre-instruction covariant exercise was used to measure participants' overall communication ability together with their capacity to engage in higher order thinking. Stage one, two and three developed the aptitudes of recognition, enquiry and synthesis through the use of both regular and non-regular geometry embedded in dual purpose activities. Sate four, moving towards conceptualisation, employed a comparative photographic composition as a measure of students' previously perceived composition. The final stage centred on an organic composition derived by the students that outlined their ability not only to communicate but also present symphonic aptitudes. The key findings for this paper are significant in terms of developing a sustainable strategy for teaching freehand sketching in Irish high schools. Instantaneous improvement resulted in participants developing an intrinsic motivation to develop their skills and engage in the activities as autonomous learners. An innovative pedagogical strategy was applied. This facilitated a cohort of thirty participants and incorporated "Pareto's Law" and the "80/20 Principle." The concept of realising and developing personal styles in the communication of compositions was a novel finding of the research. Relationships between "metacognition" and sketching competencies are discussed with implications for the exploration and development of complex solutions in plane and descriptive geometry. The paper concludes by highlighting the value of freehand sketching in developing symphonic design capabilities, the implications of this skill in terms of transferability and access of the "physical symbol system" present in the cognitive architecture. (Contains 27 figures.)