What could the ancient Germans learn from the Roman Empire?

They could learn from her culture. The Visigoths were especially close to the Romans in the later years of the Roman Empire. They fully borrowed Roman culture and the very lifestyle of the Romans. The Visigos themselves were among those who had a hand in the fall of the Western Roman Empire. So after the collapse of the empire, the Visigoths occupied the lands of Spain and the territory of southern France, where they created their kingdom of the Visigoths.