It is known that many products, both software and hardware, are not accessible to large sections of the population. Designers instinctively design for able-bodied users and are either unaware of the needs of users with different capabilities, or do not know how to accommodate their needs into the design cycle. The aim of this paper is to present a methodological design approach for implementing inclusive interface design. This will begin with a discussion about what constitutes good inclusive design and suitable measures of success. A summary of the principal methods for designing for users with different capabilities is given along with a description of a model, the inclusive design cube, that displays how the different approaches are complementary and can provide complete population coverage. Two case studies shall be used to illustrate the use of the model. The first details the design of an interface for an interactive robot. The second looks at the design of an information point for use in a post office, and shall be used to highlight the use of both the design approach and the model.