The need for continuous improvement in engineering designs of aerospace and automotive products exist in order to optimize cost, weight, volume etc. Due to the inherent uncertainties such as external loading, material properties and manufacturing quality, the prototypes of manufactured product may not satisfy all the requirements. Deterministic approaches cannot take into account all the variabilities that characterize design input properties leading to oversized or undersized structure. The present paper deals with response surface methodology where the performance functions are generated using design of experiments. These simplified linear performance functions are used for design optimization. Further, an outline of the methodology is discussed that could serve as a guideline to develop a more efficient and optimized design process. Here, the product optimization is carried out in stages starting from deterministic optimization, followed by reliability based design optimization using reliability index approach and performance measure approach to meet target reliability requirements.