User-Centered Design (UCD).

The design is based upon an explicit understanding of users, tasks and environments. Users are involved throughout design and development. The design is driven and refined by user-centered evaluation. The process is iterative.

User-Centered DesignWikipedia
Notes on User Centered Design Process (UCD)W3C
Introduction to User-Centered DesignUsability First
Looking Beyond User-Centered DesignA List ApartFebruary 1st, 2013
Government Digital Service Design Principlesgov.ukApril 3rd, 2012