The Design for Usability project aims at improving the usability of electronic professional and consumer products by creating new methodology and methods for user-centred product development, which are feasible to apply in practice. The project was focused on 5 key areas: (i) design methodology, expanding the existing approach of scenario-based design to incorporate the interaction between product design, user characteristics, and user behaviour; (ii) company processes, barriers and enablers for usability in practice; (iii) user characteristics in relation to types of products and use-situations; (iv) usability decision-making; and (v) product impact on user behaviour. The project team developed methods and techniques in each of these areas to support the design of products with a high level of usability. This paper brings together and summarizes the findings.