These five stages -- investigating goals through testing interfaces - represent my workflow in interaction design.  I apply any of the methods listed during a stage, but never all.

Investigate goals

Analyze requirements

Architect structure

Prototype layout

Test interfaces

- Contextual Inquiries

- Delphi Method

- Reverse User Environment Design

- Surveys

- Focus Groups

- On-Site Observations

- Personas

- Scenarios

- Affinity Sorting

- Model Consolidation

- Storyboarding

- User Environment Design

- Task Analysis

- Card Sorting

- Paper Prototypes

- Wireframe Prototypes

- Prototype Testing

- Usability Testing

- Heuristic Evaluation