Professional skills: excellent understanding of the source language, mastery of writing in the target language, good organizational and research skills.
Personal characteristics: well-rounded culture and intellectual curiosity, adaptability, availability, motivation, good judgment, good communications skills, efficiency, patience...
Mastery of a third language. In Europe, many translators and interpreters master three or four languages. Languages in demand, besides English and French, include Spanish, German, Portuguese, Chinese, Japanese and Korean.
Mastery in one field of specialization and the ability to work comfortably in some others. (Some universities are already exploring a variety of approaches, including double-major programs, where a degree is earned in translation plus another discipline.)
Working knowledge of computer tools.