Instead of accountability to a broad outcome that your team cannot measurably influence, create accountability to commitments made by your team members that are within their power to keep.
The stakes (and their engagement) are different when the accountability is personal, not organizational.
As a leader, it is your job to clear a path for success and recognize performance as your team members work towards accomplishing their commitments.
Always check back with your direct reports on their projects. Follow up on any projects they are working on and ask if they need help. Be approachable so that if they are struggling with a project, they will feel comfortable enough to ask for your help.
Report on weekly commitments during team meetings. Go around the room and ask how people are doing on projects, including yourself. Acknowledge any accomplished tasks. Review and update the scoreboard, then make commitments for the next week.
When members of the team see their peers consistently following through on the commitments they make, they learn that the people they work with can be trusted to follow through. When this happens, performance improves dramatically.
If you simply tell your team what to do, they will learn little. What you ultimately want is for each member of your team to take personal ownership of the commitments they make.
Do this regularly to keep accountability high within your team.