Take regular strokes, but keep the blade fully squared on the recovery. In larger boats, rowers can sit out with their blades flat on the water to help set the boat. This drill will be more challenging in smaller boats where that is not an option.
Progression
In larger boats, you can decrease the number of rowers sitting out to make this more challenging.
Note
When no one is setting the boat, keeping the rate high enough and the rowing fluid helps keep the speed higher, helping the balance.