When I first made the transition from UX practitioner to manager, I had a great conversation with Tom Spine, a colleague in the area, who helped me recognize some things to look for in designers. He directed me to his blog post Things That Are Important where he identified five principles that he recognizes in successful designers. Tom mentions teamwork, technical excellence, attention to detail, and a general passion for design that makes it more than just a job. In my work as a manager, I find it helpful to refer to these points when mentoring or coaching others, or when evaluating an interviewee.
Now with the benefit of a few years under my belt, I've taken Tom's list and expanded it a bit. To be a good designer, I think you have to be a good consultant. Whether you work for an agency like ours or work in a design department within a larger organization, you play a similar role in generating consensus, educating stakeholders and guiding non designers through the process of creating something useful and useable. To successfully bring a project to life, the designer has to carefully balance the need to bring expertise to the table and guide stakeholders, with the desire to leverage the perspectives of the entire team, including developers, marketers and business owners.
So to Tom's list, I add the following:
Facilitation. As a user experience designer, you may have the opportunity to facilitate research sessions. Much has been written on this subject (I recommend Dumas and Loring's Moderating Usability Tests as a start), and those skills are certainly important. However, just as important is the ability to facilitate stakeholder meetings, run collaborative design sessions, present alternatives and rationale to executives, etc. You have to recognize perspectives of meeting participants, understand agendas and political dynamics, bring a sense of humor where necessary, and have control of the meeting to make sure the objectives are reached. My advice here is to be prepared. Have structured activities if necessary to help orient meeting participants and move the discussion forward. Have a goal for the meeting. Plan for the inevitable off topic conversations, but don't be afraid to get the meeting back on track for the interest of time. Ask a colleague who may be in attendance to critique the meeting and have an open mind to accept that feedback.
Understands Principles of Design. The value that professional user experience designers bring to the table is that they understand the underlying principles to what makes a design good or bad. While others may just "know it when they see it", a user experience designer should be able to describe why something is working or why it is not. Being able to reference these principles to help persuade or educate team members is essential. Without a reference to these principles, opinions on a design become just that - opinions, and the opinion of the most senior member of a team will likely win out in the absence of logic or explanation.
Negotiation. Inevitably there will be tradeoffs in a design. Constraints can be technical, business, or just a matter of a difference of opinion. If you are so tightly tied to your opinion as a professional designer, and can't negotiate on different options, you stand the chance of alienating the people you are working with. If you find yourself in a position where you have a different opinion than a team member, instead of simply saying "I think it should be this way...", I recommend turning the discussion into a question back to the other person. For example, you could say, "If we try it this way, the advantages are X, and the disadvantages are Y. Do you think those are right, and which do you think is more important?" The key here is to be genuine. By asking questions and getting to the root causes of the difference of opinion, hopefully you can negotiate a solution that meets both needs.
You can be a good designer. But, if you aren't a good consultant as well, bringing your designs to life will be much more difficult. Adding to Tom's list, I'm up to 8 things that are important now. I am sure there will be others...