Crossing the Baltic Sea - Etxe I often say, to anyone who asks, that I need things half planned and half unplanned. That's how I generally live my life and that's what makes me happiest. I don't stress over things because I have them taken care of, but I have the freedom to be spontaneous with the other half of the stuff. It keeps me sane.

So when it comes to a trip abroad, I follow the same logic. For example, I'm currently on a boat crossing the baltic sea. I paid for this ticket a few days before I left the US, but I knew I could have waited until got here if I wanted to. I also knew I could have hopped on a boat to St. Petersburg if I wanted to, as it leaves out of the same terminal and you don't need a visa if you arrive via a cruise ship.

Now, this kind of half-planning only works if you get the important stuff out of the way. I made the mistake on this trip of arriving in Copenhagen at 8am without a map. I thought I was going to have internet on the plane, but it turned out I did not. When I arrived in Copenhagen, I had to turn my data on in order to download one and then fix the $400 dollar charge by paying at&t for data plan, something that really annoyed me but it was my fault. Thankfully, they aren't charging me the $400, but overseas phone/internet is really, really lame and even if you think you have it figured out, you probably don't. I could have avoided that hiccup by simple having a map ready, finding a map at the airport, or knowing a wifi cafe nearby where I could have downloaded a map.

Anyway, here's my checklist! Let me know if there's something I forgot in the comments below.

Travel Abroad Checklist

2 - 6 months before your trip

Planning

Flights & Transportation

While it depends on where you are going, it's never too early (or too late) to start looking for flights. I usually book the big one / most expensive one as soon as I can find a good deal, and I wait on the ones I know won't change too much. This also gives me freedom to plan a different route if I change my mind later, which often happens. I prefer trains and boats to flights and they usually also have more flexibility.

Also it's good to figure out how you are getting to and from the airport starting at your house. The cost of this transportation will add up and the more you know, the easier it will be. In some places a cab is the best bet, in others it's easiest to take a train or bus. The worst thing is spending too much money or getting lost before you even get to your destination.
Accommodations

I mostly travel to visit friends living in other places, but when I don't have a friend, or friend of a friend in the city, I prefer to couch surf or find an airbnb. Obviously, you can always get a hostel or hotel, but it's a much more authentic experience if you can see the city from the pov of a local. Hostels are fun as hostels, but I don't particularly like them. I'd rather pay a little more and have my own apartment. Whatever the case may be, make sure to have a backup just in case. Having an address, directions and a phone number to your backup will save you the hassle of arriving somewhere with no where to stash your luggage (I don't always do this, but I should).
Directions

Always print out maps and write out addresses and even directions to wherever you are staying, the city, the metro/bus, how to get to and from the airport (or however you are arriving) and any places you definitely want to visit. Many cities have cafes or areas with free wifi, but sometimes it won't work and it's much less stressful if you already have an idea of where you are going. If you are already in your location and have wifi where you are staying and find a new place you want to try, just look it up on google maps and take a screen shot. That way you can reference it later without having to use the internet. I like to write things out because I remember it better and I'm less likely to get lost. On the other hand, getting lost is half the fun. It's just not fun when you are tired and it is dark and raining and you don't know which way is north. And you are alone. And your phone is dead. And you've been up for 20 hours. So yeah, at least know how to get to a place with internet.
Itinerary

I generally start researching a few months before a trip and make note of things I want to do or see. My favorite thing to do is to find people on the couch surfing site that live in the city and ask them about their city. They are usually excited you are interested and will give you some recommendations that you can then further research. I love learning about different neighborhoods and what life is generally like. One of my favorite days of travel was just hanging out with my friend all day in Berlin, doing what he did in a normal day. I also like setting up meetings with people in the place I am going to visit. Sometimes just sending an email is all it takes. This current trip I didn't plan as much, but I did take down some specific things I wanted to do. Make sure you take down the address and general info. like hour, cost, etc. as it will save you time later. I showed up at two places that were between exhibitions in Copenhagen because I did not do this.

If you are going to more than one city, be realistic about what you can do. This is mostly why I didn't plan much on this current trip because I knew I wouldn't have too much time and I didn't want to be constrained by any kind of schedule. This is easier to do if you are alone. If you are with other people, it seems most time is spent figuring out what to do, so you might want to have a more planned out schedule.

I also email my parents an itinerary that has my exact travel dates, flight #s, addresses and phone numbers of people I'm staying with and such. I then have another travel guide type doc where I put the things I actually want to do. This way my parents have what they need, and I also have easy access to a list of the facts -- like where I need to be when -- while my actual activities can unfold as I go.
Contact info

Speaking of contact info, along with an itinerary, I write out/copy the following things and make a copy for myself and my parents and/or sister just in case of an emergency.

Reservations for flights, trains, boat rides
Copy of passport, ID
Copy of credit card, debit card
Copy of health insurance card
U.S. Embassy addresses and phone numbers of each country I am visiting
Addresses and phone numbers of the places where I am staying
Phone numbers of parents, etc. for my records in case my phone blows up and I can't access the internet

Check the US State Department Passports & Travel Country page
- Check the CDC
  
  All you do is pull down the menu to the country you are visiting and double check you have all the shots. If you don't, it's up to you whether or not to get them, but it is always better to know your risks.
1 - 3 months before your trip

Prep
Enroll in Smart Traveler program

It takes maybe 10 minutes and your parents will be overjoyed. It basically means the US will attempt to find you in the case that your family needs to send you an urgent message or something happens and you need to be located.
Research where you are going

While you have started doing this, now it's time to dive deep. Travel books are great, but don't restrict yourself. I check websites, blogs, social networks (like couchsurfing mentioned earlier, but also tagboard and instagram), magazines and look for films, music, books about the place I am visiting. Use the library.

1 - 3 weeks before your trip

Figure out your baggage restrictions

All airlines are a bit different and sometimes change regarding international or domestic flights. I usually write down the restrictions for each flight so I can pack for the most restrictive flight. The cheap flights are the worst and you will pay for any weight over the restricted amount, so be careful. If you end up with more than you came with, it may be worth it to ship it back.
Figure out what kind of flight entertainment/food you will have

I like to know this so I can plan accordingly. Do you need to download all seasons of the West Wing? Probably not, but always good to find out. Do you need to bring a meal or will they provide one? I always bring extra liquids as I tend to get dehydrated, but international flights generally provide meals.
Check the exchange rates

For example, in Denmark: 1 Dollar = 5.58 Danish Krone. By checking you can see if it is better to exchange some money in the states or wait. In the case of Denmark, it is much better to wait, but I wanted to have something on me when I arrived. Next time, I'll wait as there is an exchange stand literally in the baggage area at the airport.
Check the weather & local style

This will inform what you need to bring and how you need to pack. I also like to research what people usually wear in whichever place I am visiting.
Pack

Last, but not least, pack! I could write an entire post about this but my ship is docking and the sun is out, so it will have to wait.