These won't make you into an SAS commander but they may help avoid some difficulties as you travel around.

• Pay money onto the dishes by the cash register. Never put it into the hand of the cashier. Likewise they will put your change into the dish. Try to pay with exact change.
• Keep the receipt. The tax police may stop and ask to see your receipt from a goods purchase. This is about charging you the right tax amount.
• Don't touch the fruit. To avoid being scolded like a kid just point to what you want at the fruit stand and say how many. The supermarkets have plastic gloves for you to use.
• Carry a card or flyer from your hostel when going out late to show the taxi/policeman where you are staying if you can't speak (Italian).
• SIESTA. It works all year round and is a 3 hour break in the afternoon between 1-4pm. All the shops close except maybe a sandwich bar or two. Very handy in the height of summer.
• Slow down. Especially in rural areas. Shopkeepers are likely to spend 20 minutes talking to the person in front of you which is great if you are practising your Italian but not if you are going to catch a train.
• Padlocks on day bags. In crowds or at displays keep your bag on your front and padlocked.
• NEVER put anything remotely important in those cargo pants pockets. Pickpockets love them the most.
• NEVER take your day bag with passport, credit cards, guide book, train pass, plane tickets and $1000 Nikon to dinner and the pub. Take a disposable camera and as much cash as you will need. The rest can stay in the safety deposit boxes where you are staying.
• Ear plugs, flip-flops and a sarong. The SAS would agree totally.
• One noisy plastic bag only in your pack. This avoids someone hurling abuse and bottles at you at 6am when you are leaving your hostel room for the airport.
• Keep an open mind!