I went to Italy back in 2014 for about a full week, exploring Rome, Florence, Venice, and Cinque Terre. Below is a rough guide I put together for some friends who went the following year. It's a bit outdated and may have some grammatical errors but the general information should still stand.
Also super important to note: I didn't have a ton of time to see everything so my mentions are actually pretty limited. Please do check other people's suggestions and itineraries to get better insight. :)
NOT IN THE DOC
The Italian government has launched a free wifi app called Wifi Italia. I don't expect it to be great Internet, but it's free + I'm sure the government will work on making it better and faster in years to come.
Comments are open for suggestions and discussion.