In cold spraying bonding occurs when the impact velocity of the particles exceeds a critical value. This critical velocity depends not only on the type of the spray material but also on the powder quality, particle size and particle temperature. The present contribution summarizes general views and reports recent developments with respect to the understanding and respective consequences for applications. The bonding mechanism was analyzed by cold spray experiments, up-scaled single impacts of metal balls and subsequent modeling. Based on the deeper knowledge, concepts are provided how cold spraying can be tuned with respect to process efficiency and coating quality. The presented optimization procedure covers principles to increase gas and particle velocities and rules to decrease the critical velocity for bonding. By consequently following such route for typical, metallic spray materials, cold spraying, as a quite new coating technique, is already capable to provide coating qualities very similar to those of work hardened bulk material at powder feed rates similar to those of thermal spraying and deposition efficiencies of about 90 %.