When planning a new trip internationally, if you're anything like me, you probably get very excited about going. Often we put time into finding out what hotel we're staying in, what flight path to take, some activities while there, and so much more. Just remember there are a few important steps that often get overlooked but are very important.
The first one, which is very dependent on where you go and what country you are a citizen of, is to get a visa. As an American, I often am exempted from travel visas. This is not the case of every country though. For instance, I can fly to Hong Kong without having to file a visa, but entering mainland China does require one. Flying to New Zealand requires no visa, Australia required me to file an electronic visa. So far my experience with visas has been few and far between because of many agreements between USA and other countries, but remember to file these far in advance so if you need to send in information, you have enough time to do so.
The other important topic is one the I almost overlooked for my trip to South Korea... health. South Korea is a first world country, one I suspected I wouldn't need any special vaccination for... I was wrong. Luckily it was something that I ran across and did remember a good month before l will be flying to South Korea. As of a few weeks ago, my Hepatitis A and Typhoid vaccines were taken and now I have protection against those diseases.
The CDC website has a list of different regions and what vaccinations are recommended. I do highly suggest you take a look at this website and get yourself up to date for Hep A and Typhoid. These two immunizations will actually cover quite a few countries. Since I have them now, I'm covered for both Cape Town and Buenos Aires next year. Typhoid will need to be updated every so often (5 years for the oral vaccine).
Talk to your doctor, or go check the CDC site before traveling to your next vacation.