This paper investigates what works – and why- regarding capacity building. It draws on the experiences shared by capacity building practitioners through the INTRAC Praxis Programme over four years. This DGIS-supported programme encouraged capacity building practitioners to reflect on, learn from and disseminate their experiences in the field. This paper syntheses the learning from practitioners who had written 17 Praxis papers, 31 Praxis Notes, and attended six Praxis supported workshops. They have written from diverse contexts on a wide variety of themes, and yet common issues have emerged. This paper explores these common issues and highlights what we can learn from the experiences of these practitioners.