In this paper we describe QoSPlan - a generalized process for preparing information relevant to QoS-aware IP network planning. QoSPlan is designed to reduce the cost of deployment and maintenance of traditional network monitoring systems for service providers, while maintaining a sufficient degree of precision. The process involves analysis of pre-existing accounting data to estimate a network-wide demand matrix. Part of this estimation process relates to the generalization of QoS-related effective bandwidth measurements taken from a set of collected packet traces. Based on experience, we offer recommendations on how to appropriately realise QoSPlan to maximise its accuracy and effectiveness when applied to different network traffic scenarios.