Keep your map handy. At an intersection and/or perhaps at a viewpoint where a decent compass arc of surrounding distant landscape can be viewed, pull out your map, and ask others to pull out their maps. If they don’t have them handy, encourage them to keep them handy (for example, in the cargo pocket of hiking pants). Have folks orient their maps, ask them to estimate where they might be. If distant terrain features can be seen, ask them to suggest what they’re looking at and how to use those or other features to help keep track of where they’re at.
Later that same or the next day, do it again. Try to get folks in the habit of tracking where they are, of taking personal responsibility for “staying found” rather than just relying on the leader.