Although I haven't reached Rick Steeves status yet I'm proud that I'm on my eighth trip across the pond and have learned a great deal about travelling in foreign countries (now 27 of them) and I'm happy to share some tips here.
First off - 'do your prep.' If you're going to a brand new company learn a bit about the culture and history of that country. Europe is draped in history and their customs and various systems are often 100% different from North American norms so it's wise to be prepared.
Wikipedia and YouTube are your best friends and now Podcasting is a huge help. A simple search of the City or area you're going to will yield a goldmine of information - and video - and help you get to know a few of the landmarks you'll be visiting.
Once you get to your destination you'll be shocked at how much you DON'T know and my common line upon hopping the plane home is "if I'm ever reincarnated and come back to life I'm going to pay attention in History class next time."
Currency is different all over the place....and even though the Euro was supposed to cover most of Europe there are a few countries that don't accept the money OR take it 'hesitatingly' and often you will get short changed in the exchange.
We travel with very little cash as there are bank machines everywhere - but again some do NOT have English on them so it can be a bit challenging getting cash out when needed.
We also carry two different credit cards - American Express and VISA for use - because you can run in to merchants that won't accept one or the other or for that matter credit at all.
A hotel Concierge is your best friend and can be of huge assistance for everything from giving safety tips or calling a cab (or Uber in some cases) as well as helping with any language issues.
Many hotels have airport pickups as well...which can be extremely helpful after a long tiring trip.
There are several apps that do the conversion for currency all over the world and it's wise to have one of those on your smartphone.
Ditto 'language' conversation. Even knowing a few key terms can be helpful.
Most countries it's very easy to get along with just English - though France has had a few challenges for us...like a waiter picking up the menu and walking away when we asked for an English one. He never returned.
Speaking of smartphones roaming is incredibly expensive. I put mine on Airplane mode and rely on wifi (which is readily available throughout most of Europe - except in some small towns) and use my SKYPE account to call back home after I've checked messages on my phone.
Electricity is different all over the world too so you'll have to be a plug that adapts to the various countries you are visiting. Be careful though as you need multiple units. The UK, for example, has their own unique system and it's different from most of Europe.
Caution at airport arrivals. Many cities have 'rogue' drivers who look like any other cab driver except they are IN the airport and grab you at the luggage area and aggressively direct you to their cars. They are not licensed and some drive like madmen. On a Paris run with my daughter one was going over 200 kph as we screamed at him (in English) to slow down.
Heathrow has a high speed link from the airport/downtown - Paris has their Metro (subway) that can save you money and avoid congestion.
UBER can be gold especially in cities where language problems can occur. Simply order your ride share in the hotel lobby - take the ride without worrying about any 'lost in conversation' problems.
A few safety tips:
1. Tell your security system provider you will be away and give them two 'contact' people in case of any needs.
2. Give a copy of your itinerary to other family members mrs so that they know where you are at all times. Give them hotel names, your travel agents name, (if applicable) in case anybody back home needs to contact you.
3. Put a business card in your luggage with all your contact information as well - including phone, email, etc. - so that there are multiple ways of getting hold of you.
4. Pickpockets are huge in Europe - many travel in teams. One distracts you or bumps in to you and bingo you're hit. Watch your purse or bag when you put it on the floor at a restaurant or where you stop. These are 'pro's' and if you're not careful that bag will be gone in a blink. On a plane or a train loop your arm through the straps on the bags because they also unzip a bag and quickly grab anything they can while you sleep. I 'somehow' lost an iPod on a train without a trace.
5. Group tours are the best so that you can all the local info - try to stay close to them - and especially at night be aware of your environment.
Set up a special Facebook site so you and your travelling companions can upload photo's...it's free.
REMEMBER to use the 'check in' button feature as it geo tags the photo to the exact spot you were standing when you took it. After a long tour, believe me, you'll have so many pictures you'll have a hard time remembering the city/town/area you took that picture especially with trying to remember a remote locations name.
6. Travel light. Leave your expensive jewellery and watches at home. No need to have them on hand 'just in case.'
7. Pre book as much as you an ahead of time. There's nothing worse than getting to a location you wanted to see and there's a long line up to get through.
8. If you're going to London download the Metro guide - it's the biggest subway system in the world and is several levels deep.
9. If you're going to the LOUVRE Google 'secret entrance' - and you'll find a set of stairs across the street from the building(s) that is used by the locals and those smart enough to find it. No signage - and it leads directly to a tunnel and shopping area inside the Louvre with machines to buy your entrance ticket.
10. Buy a cell phone package - again - just in case. There's lots of free wifi available for phone/ipad use but if you get separated from a group - or lost - it can be a life saver. Plus 'text' where possible and let your friends back home know your location of destination in case they need to reach you.
Take as many tours as possible. The Red/Blue double decker buses are cheap and circle the city stopping at various tourist attractions. It's hop on - hop off - and you can make the most of your time using them. Some have dual routes so check out what the best one is for your desires.