Improved complex system design methods can lead to innovative, efficient, and robust product designs. This research aims at improving the design of products that compose a portion of, or exist within, a complex system. Before attempting to improve product designs, one requires a better understanding and characterization of complex systems. One method to characterize optimized and robust complex systems is to use the Theory of Highly Optimized Tolerance (HOT). The theory states that highly optimized and tolerant complex systems are robust in conditions for which they were designed, but fragile in the face of unanticipated events. Highly robust and optimized complex systems are abundant in the biological domain. In fact, nature represents a vast resource for innovative solutions to varied design problems. Leveraging these solutions to solve engineering problems is often referred to as biomimetic design. This research analyzes twenty bio-inspired engineering products including the biological system from which they were derived. The HOT theory is used analyze the biomimetic systems and identify the inherent characteristics that make the designs robust to their environment. These characteristics were reviewed to identify common features and trends present within the information transfer between the biological and engineering domains. Finally, the inferred features and trends were abstracted into usable guidelines stated as nine biomimetic design guidelines. Similar to the forty Theory of Inventive Problem Solving principles, these bio-inspired guidelines could aid engineers in developing innovative and robust solutions to design problems. In fact, a similarity between some of the biomimetic design guidelines and TRIZ principles is observed. This correlation suggests that solutions perceived as innovative in the engineering domain match those in nature.