Is it necessary to leave the tip at the restaurant?

No, waiters are paid with regular salary. But they will be happy if you do it.

Where you can buy a ticket for the public transport for example for the bus?

Only buying the ticket in shops called Tabacchino.

Nowadays on the bus, paying with the credit cart.

You can always ask for help speaking in English.

You must separate waste in specific waste bins.

Driving in Italy is forbidden without an European driving license.

False, but you need a International driving license.

Every region and every city even has its own local dish and drink.

Italians are messy when they drive and also when they are in line to pay.