First - check for visa requirements and work on getting the necessary visa.
Know the language preferences and keep a handy guide book in case it is totally foreign to you.
Check for weather and pack accordingly, it is quite a let down when you land in a new place and are not well prepared for the climate there.
Read about the place and check for restaurants, eating options, food available etc.
Check for transportation options, rental car, pulic transport, be prepared of what you might need to do in order to be mobile.
Know cultural norms so you are respectful and considerate to the country you are visiting. Don't assume the same code of conduct and dressing is followed everywhere around the world.