Get out of the office. Go for lunch. The applicant will feel more comfortable and open up, and you'll get a glimpse of the real person behind the resume. Another important skill you should look for is creativity. It's crucial to survival to keep your training new and exciting, teach in different ways and stay on the leading edge.
Creativity is vital for keeping training exciting, fun, effective and applicable to the business.
Make sure that all training team members also interview the candidates. Good team dynamics create a productive, happy environment that customers can see. If you want to test potential candidates, you can conduct a skills assessment of their technical abilities. Have candidates train you to assess their presentation skills, or ask them to relate the training to your industry. Still, those important gauges of a good instructor don't necessarily make a winning organization.