Focus

I think the best way to figure out how to motivate someone is to first try and figure out the reason for them falling behind or for their lack of focus. Maybe take some time to sit and chat with them over coffee or lunch. Once the root of the problem has been determined you can figure out the best strategy to help them refocus and get back on track. There may be several reasons for them falling behind so I would see if there is any way I could assist them in creating a daily to do list or weekly planner to help them stay on top of their tasks. After the plan has been put into place I would then occasionally check in with them and see how they are doing to reevaluate the plan and make adjustments as needed.