Proactive government is a promising approach to user-friendly public services. By acting proactively instead of reacting, governments reduce the interaction effort of a public service for the user and, in doing so, increase its user-friendliness. However, implementing such proactive services in practice is challenging and requires the redesign of the according processes. For example, the data that currently is provided by the user, now has to be collected by someone else. The goal of this paper is to identify reoccurring challenges in the redesign of processes for proactive public services and to develop strategies to overcome them. We analyse business processes from nine public services and conduct ten expert interviews with practitioners. We synthesis the reoccurring challenges into three implementation dimensions and present three implementation strategies. The implementation dimensions inform the feasibility of proactive services in practice and the strategies can be used by practitioners to streamline their efforts to provide user-friendly public services.