Internet of Things is a technology paradigm that enables the interaction of devices and communications technologies with embedded software, integrating different areas and multidisciplinarity. It is built from smart objects, that relies on things interaction and information exchange, which can lead to development challenges. This paper presents research towards the definition of a framework to support the engineering of IoT software systems. From a literature review, we introduce six IoT facets representing knowledge areas and topics to consider while engineering IoT software systems. The proposed framework uses them to have a multifaceted perspective of the IoT problem domain. Three steps going from Project Characterization to a strategy to support decision-making for development compose the framework. The article presents a real case scenario of a shrimp farm used to illustrate its use.