One question I get asked a lot is: "Should we pull Euro out in America and bring it with us or should we wait?" My answer is this, WAIT. I hear that you get charged for exchanging money in America. I would wait till you get to Europe and use an ATM. You only get charged the normal fees and you have money as you need it. Make sure your bank knows that you are going to be in Europe and everything should be fine.
By the way, most shops in Europe don't except bank or credit cards. You will want to make sure you have cash on you. Bigger chain stores should take cards, but anything less than the big names have a higher possibility of not excepting them.
Cell phones: Most bigger companies offer some sort of travel plan. I am on the fence on whether or not I feel it's worth it. On one hand, it would be nice to double check reservations, or if you are winging it, you have the ability to make reservations. On the other hand, they aren't always reliable. I am a planner. I usually have everything figured out before I go anywhere and don't even use my cell phone for anything other than for its clock. So as far as my opinion goes, I am 50/50. This one is all on you.
Where to stay: In America I always lean towards a chain hotel that I know and trust. But in Europe I find that they are not that convenient. There are Best Westerns every now and then, but I would never stay there. I like to lean more towards the Bed and Breakfasts. They are a lot cheaper, a lot cleaner, and a lot more accommodating. I find that I get more ambiance of the location when I stay out of chain hotels.
As a side note to this, when booking a room, know that single does mean one person staying in a single bed. But double does not mean two single beds. This room is called a double because it's made for two people. A double is usually two single beds pushed together to form the size of a queen bed. It is extremely common in Europe that couples have their own mattress and their own set of linens.
Electronics: My rule of thumb is this: If it is something that a business person would travel with then it will most likely work. So laptops, eBooks, cell phones, and tablets are going to be dual voltage. You just need to pick up plug adapters. Now you have to check on other things like hair dryer, hair straightener, and electric razors but you will be surprised that a lot of them tend to be dual too.
Another thing I get asked a lot is if that person looks foreign. The answer is yes. Most likely you are not going to blend in to a native. But it doesn't matter. I have yet to be somewhere that I felt discriminated against. I find that more people are intrigued and are inquisitive about me. They aren't afraid to ask questions and have a general conversation.