You can't motivate a group of people or a Team. You have to motivate people individually, and that motivation has to be in an environment in which that person has a goal - something they want to accomplish in their lives.
Do what's right! Do the best you can and treat others the way you want to be treated because they will ask three questions: (1) Can I trust you? (2) Are you committed? (3) Do you care about me as a person?
What you are capable of achieving is determined by your talent and ability. What you attempt to do is determined by your motivation. How well you do something is determined by your attitude.