In general, people seem to think of international travel as hard to achieve, and most never get around to trying it. When it comes right down to it, though, international trips aren't necessarily harder or more expensive than many other vacations, and they can often be more rewarding. If you're trying to plan an international trip but are getting bogged down in the details, here are the most important steps to keep in mind.
Make sure you have a valid passport. If you don't, figure out how to get one. In the US, you can get information and forms for this process at your post office.
Learn whether the country you would like to visit requires a visa. In this context, a visa is a stamp or sticker in your passport that gives you permission to enter a specific country. Visas usually cost a relatively small fee and must be obtained before traveling, which is an easy process but one that can take several weeks or more.
Figure out whether you will need any vaccinations. In particular, tropical destinations may require extra vaccines, or you may choose to get them because of increased risk of serious diseases in these countries. Start planning for this as soon as possible, since some rounds of vaccines need to be given over a period of months.
Research your financial options. You will need to exchange some money before arriving, which you can do at an airport, but you will get a better rate by doing it at a bank before you leave. Also, figure out whether you can use your debit or credit card internationally, and whether you will be charged a percentage of all purchases for doing so. Another option is travelers checks, though these are rarely the most convenient anymore.
Learn a little of the language of the country you will be visiting, if you don't know it already. An international trip is a great excuse to learn a new language, but if you aren't interested in doing that, at least learn a few useful phrases like "Do you speak English?" and "Where is the restroom?" If this is too daunting, choose one of the many locations where English is the common language.
Read up on the local culture and popular destinations. This will help you get the most out of your trip by learning what is unique about the place you will be visiting.