From your target date, work backward and figure out who needs to do what every week. Ask people to set and publicly commit to their weekly goals—this creates accountability. Periodic reviews can also be a good way to sustain momentum. I know a team who uses this technique expertly, sometimes even hosting two meetings a week to review progress and discuss urgent priorities. If your team is juggling a number of different tasks, order those by what matters most—which ones are “critical path” and which are “nice to have”? Always tackle “critical path” first.