The below tips are with the typical study abroad student in mind, but may apply to a broader audience.
1. Go to a Supermarket
In my experiences across Europe, it is much cheaper to buy things from supermarkets when compared to corner stores, pizzerias, or road side vendors. I have saved so much money by buying bottles of soda and water inside a supermarket instead of somewhere else. Supermarkets are all over the place and you usually pass them without even realizing it.
2. Don't Be Afraid to Get Lost
I have stumbled upon the most amazing things in Rome when I was lost. I love to tell the story of how I stumbled onto the Pantheon the first weekend I was in Rome. Now, if I am bored I love to play the "Let's Get Lost" game - not only are you learning how to navigate a new city, but you never know what you will see!
3. Spoil Yourself, Take a Tour
Sometimes it is worth it to pay the extra money and take a proper tour of a museum or attraction. Tours put everything into context and help ensure you see everything important there is to see. There are a few free audio guide tours in iTunes - I found some on Rome by Rick Steves. They're fun!
4. Travel With A Tour Group
Bus2Alps and Euroadventures are two great examples of tour groups. You travel with the same people for the whole trip and have the opportunity to make new friends. Part of traveling is meeting new people and this is an easy way to do it!
5. Your Bank Matters
Before you travel ask your bank if they have any affiliations in the country your going to. Bank of America, for example, is affiliated with BNL in Italy. If you take money out of a BNL ATM, you do not get charged a fee. Any other ATM, however, you can expect at least a €5 surcharge!
6. Don't Worry, It's Okay to Eat McDonalds
Eating McDonalds is part of the experience, too. Just as you are traveling to a new country to try to understand their culture, eating at McDonalds is a good way to analyze how the country you are in portrays American culture. Also, by looking at the menu,you gain a better feeling for what the taste preferences of the country you are visiting are.
7. Buy a Souvenir
It doesn't have to be anything fancy, but should be something you can find anywhere you go so you can collect them. I'm collecting postcard books and shot glasses while I'm over here - they should make up a pretty cool display when I get home!
8. Wing It
You don't have to plan out every detail of your trip. When you get to the hostel or hotel ask them for a suggestion- they're usually pretty good.
9. Go People Watching
I love going to a piazza by my apartment, sitting on a bench, and taking it all in. There are artists painting, musicians playing their guitars, people posing for pictures, kids playing, lovebirds talking, and tourists being...tourists. Do this especially when it's a nice day out.
10. Watch for Pickpockets
While I've been here, five of my friends have gotten pick pocketed or had their purse stolen. One of them realized it and chased the guy down - it worked out fine, but s not something I would recommend completely. Everyone else has not seen their wallets or purses since. In order to avoid getting pickpocketed,I do one of two main things. If I am wearing a jacket, I take a small amount of money out of my wallet and put the money in my pocket and the rest of my money and my wallet in an inside pocket f my jacket. If I am not wearing a jacket, I put some money in one pocket and the wallet with the rest of my money in the other. I push the wallet all the way down and put something else like a bottle of Purell on top of it. This makes it much harder for the pickpockets to gain access to your wallet.