In the workplace, what is the best approach in order to respectfully disagree?

In the workplace, what is the best approach in order to respectfully disagree? Some people are better than this than others. If you are mentoring someone in the workplace that is having difficulty with this concept, what recommendations would you have for someone who is having trouble with being open minded? If you are working in a team and someone is being disruptive in this type of scenario, how would you address?