If you want to improve the productivity of a work team, you won't get the job done with slick motivational techniques or magical motivational tricks. You will get the job done with solid management. Here are some things you can do.
Make sure your expectations are clear. It's amazing how often they're not. Check for understanding.
Give frequent and usable feedback. People want to know how they're doing.
Make lots of small course corrections. Take every contact with someone who works for you as an opportunity to coach, counsel, correct and encourage.
Be fair. Make sure the consequences match performance. Non-performers should either improve or leave. They poison the team.
Help people grow and develop. Adults love to learn.
Give the people who can handle it as much control as possible over work life. If you're doubtful, try giving them control and see what happens.
Help people understand how that they do is important to the team and the company.
Celebrate your wins and your winners.