The easiest and cheapest way to get your euros or pounds is to use a bank ATM to withdraw using your chip debit card. With some banks, you can only take out a max of 200 euros at a time at these ATMS so plan accordingly. You also usually get charged a service fee of $2-5 by your bank or by the bank that owns the ATM each time you withdraw. So rather than taking out several small amounts, go for the max of 200 euros each time to cut down on the charge. If you bank lets you withdraw more than 200 at one time, then go for it! Currency Exchange shops that are in airports or around tourist areas are notorious for not giving a great exchange rate. When in doubt, you can always look up the current exchange rate on your phone to check to see if you are getting a good rate or not. Be sure your bank debit card does not charge you a foreign transaction fee. Some charge 5% per transaction which can really add up. Also be sure your debit card is a Visa, is chip-and-pin enabled (most are by now) and that you notify your bank of your travel plans so they do not lock your account. If for some reason you have trouble getting cash out of your checking account (like I did in Morocco) you can also use a cash advance from your credit card to withdraw money, but this usually comes with some restrictions or with an interest charge so be sure to pay the card off asap, online if you can. I ended up using my Chase United Explorer card to withdraw cash in Morocco when the ATMs wouldn't accept my Visa debit card.
Credit Cards and Restaurants
Chip credit cards are widely accepted. When you are ready to leave, let the staff know you are ready to pay and tell them you are using a card. You can hold the card up politely if there is a language barrier. The wait staff usually tells you verbally what you owe or they place a ticket down at your table and then you are expected to give them your form of payment. If it is a card, they will bring a handheld machine over to you and run the card in front of you, they will not take your card away from the table. They will sometimes ask you to choose whether you want to pay in euros or USD – always choose euros. You will get a better exchange rate. If you are paying in cash, they will usually make change in front of you. Be aware that smaller, family run restaurants and snack stands don't always accept credit cards because of the fees so be sure to have cash as a backup.
Free public restrooms are usually available at parks or larger tourist areas. Many public restrooms in squares, plazas, and train stations (especially in Germany) have turnstiles that require a one euro coin (usually need exact change). Other restrooms in restaurants or food halls have an attendant. Although it's free to use, you are expected to tip the attendant a euro (or as close as you can get to it with the change you have). They are usually sitting at the entrance of the bathroom and there is a plate where coins are placed. We often found ourselves stopping into cafes to have a beer, just to use the free restroom. Another note on bathrooms - bring hand sanitizer and a pack of Kleenexes, because the soap and toilet paper situation is not always great in the public restrooms. The bathrooms with attendants are usually well stocked and very nice!
Space is precious in Europe and as a result, hotel rooms are smaller. You will still get everything you need, just be aware that the space will be smaller - but who cares? You won't be hanging out in your hotel room anyway - it's Europe! Many hotel rooms have the option of 2 twin beads or a full sized bed for 2 people. The beds often come with 2 separate blankets, one for each person. Sometimes the twin beds are pushed together into a double size bed. Read your hotel options carefully before booking if you have any particular preference on this. Hostels in Europe are actually really nice, not like the hostels in the US. They have communal areas where young people hang out and many of the nicer hostels even have private rooms just like hotels (for extra money of course). I have a thing about sleeping in a room with other people, and I don’t travel alone much, so I’m not a frequent hostel user, but I have rented a private room in a hostel that was great!
Consider trains vs. planes
The train system in Europe is amazing. There are several high speed trains and local trains that can get you to several major cities. The ticket prices are usually very good too. Not every city is super well connected by train however, and if you are planning to visit two cities that are very far apart (like Paris to Lisbon), consider flying on a cheap, budget airline like Ryan Air or Easy Jet. These airlines have nonstop flights to several cities for pennies, and most are under 2 hours. Always look at the train travel time and weigh that with the flight options. I would rather take a 1 hour flight even with the added airport security hassle, than an overnight train or a train that takes more than 6 hours. That time can really cut into your trip and the quality of sleep you get on an overnight train is not great.
Avoid the feeling that you "have to see it all"
It's easy to feel like you need to visit every city in Europe once you make the financial investment and the time investment to get there. But try to plan realistically and avoid stretching yourself too thin. You will be taking it easy on your first day, and the day you leave, you won't be doing any activities. You will want some flexibility to sleep in late, stay up late, or tapas bar hop. I am guilty of town hopping one too many towns and feeling like I glazed over a place. I over planned my Spain trip and ended up regretting the first few days. The truth is, you will be back to Europe! Enjoy where you can go in the time you have, and save something for your next trip. I know, I know - easier said than done.