When starting data warehouse design, I’d first focus on the business questions the warehouse needs to answer. Before selecting tools or schemas, decide on the primary data sources, reporting requirements, users and anticipated amount of data. It also enables us to clarify the frequency of data updates, and the management of historical data. Don't make it too complicated so that it can't be kept up if needs evolve. For more complicated integrations or when scaling is a concern, it's also helpful to speak with an expert like Datalance to ensure that the overall plan is correct prior to implementation.