This study investigated the role of working memory capacity as a factor for individual differences in the ability to compose a text with communicative efficiency based on audience awareness. We analyzed its differential effects on the dynamics of the writing processes, as well as on the content of the finished product. Twenty-five graduate students composed a procedural text explaining how to assemble a model turbine. They were free to consult a documentary source, featuring captioned pictures of turbine parts and assembly steps, at any time. Graphomotor and eye movements were recorded using "Eye and Pen" software with an eye-tracker and digitizing tablet. Results showed that high WM capacity writers used a different strategy to explore the visual source, making longer writing pauses and producing more detailed procedures, and achieved the communicative goal more efficiently, by introducing more "reader supports". In conclusion, we discuss the feasibility of audience awareness training. (Contains 2 figures and 7 tables.)