If the project was a team project, look for signs that she took a leadership role. A candidate might say: "We were working on X, but the boss said Y and the client said Z." I'll ask, "So what did you do?" A good answer to this might be "I got together with the other members of the team and wrote a proposal." A bad answer might be, "Well, there was nothing I could do. It was an impossible situation."
Remember, Smart and Gets Things Done. A good way to tell if somebody Gets Things Done is to see if historically she has tended to get things done in the past. In fact, you can even ask her to give you an example from her recent past when she took a leadership role and got something done - overcame some institutional inertia, for example.
Joel On Interviewing 9: Leadership