In a night attack maintaining control of your troops can be difficult. It is hard to know where they are, and hard for them to know where they are located. Using very distinctive markers, like roads, streams or other lateral objects can be helpful as phase lines to control movement.
Artillery can be difficult to control too at night. The field telephone cables can be played out as the troops advance so that communication can be maintained with the fire direction center. The biggest problem is that the infantry will advance into the artillery fire.
The momentum of an attack is difficult to maintain at night. Troops become frightened when they think they are alone. Stopping to fire, it can be difficult to regain the urge to move forward again. Non-commissioned officers are critical to keep the troops moving. In the Soviet Army the Commissar and his NKVD henchmen often helped to urge the troops forward.