Currency Exchange
Texas Currency Exchange is a great way to go if you don't want to use ATMs or if you just want to make sure you have currency before you get going on your trip. They have a very low fee, and seem to be the most competitive in the market

Converters/Adapters
Easy to get at Walmart, Target, Best Buy, and certainly online through those stores or Amazon

Neck Wallet
Also extremely easy to find online with Amazon or Walmart

Credit and Debit Cards
Most places now only accept cards with a chip in them. You can call your credit card company and ask them to send you a new card (same number, but with a chip in it). Also ask them at that time what their Foreign Transaction Fee percentage is. You want to try to get a card that has a percentage between 0-3%. That is the best range. Obviously the lower, the better.

If you are comfortable using ATMs, do fewer and larger withdrawals to reduce the number of fees. Also, this is how I get foreign currency. I wait until I arrive at the airport, I find an ATM, and I select to withdraw my foreign currency there. That way, I am only paying an ATM fee and the exchange rate. I am not paying a currency exchange office for their services.

Make sure you call your credit card company and bank, and let them know you are traveling so they do not flag your card for fraud!
Ask them if their is a pin number associated with your card as well. This will be needed at ATMs and any time you charge your card.

Tipping
Tipping is nice when you have enjoyed your service. 2-5 euros is pretty common in most countries for 1-2 people (for restaurants, bellhops, etc). To be safe, you might want to go with 10% if you have really enjoyed your service. Do check your bill though, as some countries will include a service charge - that is their way of including gratuity.

Vouchers/Booking Confirmations
Some hotels will want your voucher or the part of your paperwork that has the hotel reservation. Because they sometimes will acquire this from you, I make copies of my paperwork.

Cell Phones
Each cell carrier has different plans and rates, so call your personal cell carrier if you want to add an international plan while you travel. If you do not want to add a plan, make sure you turn off your Data Roaming on your phone, so that you do not accidentally get charged.

Packing Tips
Some of the older buildings in Europe do not have good circulation, so bring a little handheld fan, even if it is winter.


SAFETY TIPS
Backpacks can easily be tampered with - I suggest messenger bags.

Never leave your passport unattended, unless it is in a safe in your room.

It is extremely difficult to get basic drugs in Europe. They do not have your standard decongestants, antihistamines, etc. For your medical safety and comfort, bring all of this from home! The pharmacies, aka apothecaries, only have face creams, chapstick, vitamins, etc.