"Your process is what enables you to do good work."
— M. Monteiro, Design is a Job

A designer is a problem solver, in a sense that it´s expected that he/she is to work with all the stakeholders in a project — dealing with their goals and expectations — solving multiple problems while still keeping focus on the user, design and usability principles.
That comes with a process, and this is what I usually follow:

1 — PROBLEM DEFINITION

In order to solve a problem, a designer needs to understand it. This goal is mainly achieve by interacting with the stakeholders where is intending to answer questions like: Who are our users? What is the main goal of the system? What is the message that is supposed to convey?
Main results: Statement of the project, initial version of the functional requirements document.

2 — RESEARCH TO UNDERSTAND

One must be able to understand what has been done by others from a design and usability standpoint, thus allowing for a proper analysis and consequent lessons learned from its successes and failures. The goals, requirements and inspirations are part of the research and experimentation, where low-fidelity prototypes are created giving a sense of order.
Main results: Interaction workflows, functional requirements specification and initial version of the mockups.

3 — SOLUTION PROPOSAL

Having the low-fidelity prototypes is important to transfer ideas into something concrete, in order to collect feedback. The high-fidelity prototype should be as complete as possible in order to serve has a guideline to the implementation team.
Main results: Mockups, Interaction workflows, Low-fidelity prototypes.

4 — TESTING AND LEARN ABOUT IT

The design and user interface guidelines can be applied in a variety of creative ways, but to get the users to understand what is presented and in fact appreciate the interaction, is a different story on its own. We are never sure until we get the users to validate our ideas. Testing is an important way to validate if the system meets the goals that were previously defined.
Main results: Test Plan, Users recruitment, Methodology definition, Test results, Next steps definition.

5 — CLIENTS ARE NOT MIND READERS: PRESENTING THE WORK

The biggest myth in the field of design, in my opinion, is that good design sells itself. A designer should be able to present the solution by explaining why is his/her decisions are able to solve a business problem. Besides presenting (or selling), the designer needs to be able to understand and interpret the client’s feedback.