Energy efficiency in buildings has emerged as a critical aspect of sustainable development and environmental conservation. This research paper presents a comprehensive review of energy-efficient building design strategies, technologies, and practices. The paper covers Energy modelling and simulation with eQUEST Software that can be used in the designing, development, and operation of buildings to increase its energy efficiency. This includes passive design features, such as building orientation and envelope, as well as active systems, such as HVAC, equipment, and lighting. Moreover, it highlights the role of building regulations, certification systems, and occupant behavior in achieving energy efficiency goals. The paper concludes with a discussion of future goals in energy-efficient building design.