Sludge recovery from “wastewater treatment plants” (WWTP) is an important aspect of the wastewater treatment process as it allows for the reuse of valuable resources and the reduction of waste. In this review, we examine current practices and tips for sludge recovery from wastewater treatment plants. We first discuss the various types of sludge produced in the treatment process, including primary, secondary, and tertiary sludge, and their respective characteristics. We then review the different methods used for sludge recovery, including thickening, dewatering, drying, and their respective advantages/disadvantages, and provide tips for optimizing sludge recovery, including proper sludge management, optimization of treatment processes, and incorporation of energy-efficient technologies. In parallel, we present an overview of the production, operation and nutrient composition of these sludges. Overall, the aim of this study is to provide an overview of sludge recovery in wastewater treatment plants and to offer practical insights for improving the efficiency and sustainability of this important process as well as the valorization of this important raw material.