The person with the right qualifications isn’t always your best choice. The single most important aspect of your business is your culture, and you should consistently look for team members who evoke, maintain and build your current culture. If your environment is fast-paced, upbeat and communicative, you probably shouldn’t hire someone who is slow to act and lacks social skills — even if he does really good work.
When you really have a team that gets along, they’re happier, and happier teams always do better work. When you’re doing culture screenings, ask questions that get down into their personality. One of my favorite interview questions is “Tell me a story.” It forces people to think on their feet and you learn about them personally. You could also use personality tests to help them screen new hires.