Be very clear about the job description. Focus on technical and administrative skills the person needs in order to perform the functions. When advertising for the position, be specific in the skills the candidate must have. Remember, you are competing with other companies for the best qualified. When interviewing, make use of situational questions.
Past behaviour is very often a determinant of future actions.
Hope this helps. If you have more specific questions, please feel free to contact me. First, you must carefully document all the requirements of the job, including the skills, knowledge, etc. Then you must document the personal qualities needed to be successful in the job. For example, some jobs require a strong goal orientation, others require careful attention to detail, others require exceptional communications skills, and so on.