In this paper, a simplified approach for the design of thin-walled laminated composite beam structures is presented. For this purpose, structural efficiency metrics have been developed that allow for the integrated selection of layup sequence, materials of construction, and cross-sectional shape of laminated composite beams. The structural efficiency metrics are plotted in design charts for axial, bending (in both cross-section’s principal directions), and torsional loading conditions. The design charts provide the designer with an accurate and efficient approach for the selection of the optimum fiber direction, number of layers in the laminate, and mass of the overall structure. The results are generated for two different sizes of envelopes to analyze various cross-sectional types and sizes. It is shown that the design charts can be applied to single open and closed loop cross sections as well as multi-cell sections. The proposed simplified approach and developed design charts have been used for increasing the bending and torsional stiffness of a laminated composite robotic arm. The results show that the design charts can be used to accurately predict stiffnesses and deformations and assist the designer in selecting the various parameters that govern the performance of laminated composite beams.