In virtual reality (VR), interactions may fail when users encounter new, unknown, or unexpected objects. We propose using feedforward in VR to help users interact with objects by revealing how such objects work. Feedforward lets users know what to do and how to do it by showing the available actions and outcomes before an interaction. In this article, we first chart the design space of feedforward in VR and illustrate how to design feedforward for specific VR interactions. We discuss starting the feedforward, previewing actions and outcomes, and returning the virtual world to its state before the feedforward. Second, we implement three real-world VR applications to show how feedforward can be applied to multistep interactions, perceived interactivity, and discoverability. Third, we conduct an evaluation of the design space with 14 VR experts to understand its usefulness. Finally, we summarize the findings of our work on VR feedforward in 15 guidelines.