The paper discusses the optimization of norm-conserving Vanderbilt pseudopotentials to improve their accuracy and computational efficiency. The author introduces a new formulation for optimizing the convergence of plane-wave basis sets, which can be applied to positive-energy atomic scattering states and enhances the continuity of the pseudopotential. The generalization of norm-conservation to multiple projectors is reviewed, and the method is tested on a group of solids representing various types of bonding and elements from the periodic table. The results show that the optimized norm-conserving Vanderbilt pseudopotentials (OV) outperform the Kleinman-Bylander (KB) pseudopotentials in terms of accuracy and convergence, particularly for materials with shallow core states. The OV pseudopotentials are found to reproduce all-electron results more accurately, with minimal changes in the local potential and core radii. The study concludes that the accuracy of OV pseudopotentials is primarily limited by the underlying density functional approximations, and the open-source ONCVPSP code is made available for further research.The paper discusses the optimization of norm-conserving Vanderbilt pseudopotentials to improve their accuracy and computational efficiency. The author introduces a new formulation for optimizing the convergence of plane-wave basis sets, which can be applied to positive-energy atomic scattering states and enhances the continuity of the pseudopotential. The generalization of norm-conservation to multiple projectors is reviewed, and the method is tested on a group of solids representing various types of bonding and elements from the periodic table. The results show that the optimized norm-conserving Vanderbilt pseudopotentials (OV) outperform the Kleinman-Bylander (KB) pseudopotentials in terms of accuracy and convergence, particularly for materials with shallow core states. The OV pseudopotentials are found to reproduce all-electron results more accurately, with minimal changes in the local potential and core radii. The study concludes that the accuracy of OV pseudopotentials is primarily limited by the underlying density functional approximations, and the open-source ONCVPSP code is made available for further research.