How do I get the bill at an Italian restaurant?

Ask for it: "il conto, per favore", or catch the waiter's eye and mime writing. It will not come on its own, and this is deliberate — bringing an unrequested bill would be rushing you out, which is the opposite of what a meal is for. Tables are yours for the evening, and nobody is waiting to flip them. This is the flip side of service that can feel inattentive: the waiter isn't checking on you every eight minutes because that would be interrupting. Wave when you need something; you'll get immediate, competent attention and then be left alone again.