A handful of phrases will carry you through your first day in Florence:

Italian	English	When
Ciao!	Hi! / Bye!	With friends, family and people your own age — for arriving and leaving
Buongiorno!	Good morning / Good day	With anyone, until mid-afternoon
Buonasera!	Good evening	From late afternoon onwards
Come stai?	How are you?	To someone you'd call tu
Bene, grazie. E tu?	Fine, thanks. And you?	The standard reply
Piacere!	Nice to meet you	When you meet someone for the first time

Two sounds to get right from day one: ci sounds like English “chee”, so ciao is “chow”; and every vowel is pronounced clearly — piacere is “pya-CHEH-reh”.