If you have a job now, be prepared to explain why you’re leaving it. “I hate my boss,” is not a good answer. Be tactful, and focus on the growth opportunities the new role you’re interviewing for will permit (or focus on some other practical issue, such as the need to move to a new location). For example, “I enjoy the work I’m doing now, but I’d like to spend more time in court. That’s why this position handling contested child custody battles are perfect for me.”