Clothing is a must. Bring a variety of clothes and accessories but focus on basic pieces like pants or skirts, tops and shoes that are easily cleaned and versatile enough to wear in a variety of situations. Bring two dressier outfits as well for special occasions. Study the clothing norms in your destination. For example, if you are a female and you are headed for a conservative country, avoid bringing tight or short clothing. You do not have to dress like a native, but you probably do not want to stand out as a foreigner either.
Be sure to get enough of your prescription medications for the duration of your trip. Your prescriptions are unlikely to transfer abroad and you may have a difficult time obtaining your medication. In addition, pack hard-to-find personal grooming products like your favorite hair products or makeup as well in case you can't find something similar. You will probably be able to find basic health and beauty aids, but bring anything that you do not think you can live without for the duration of your trip.
While you can't leave home without your passport and driver's license, you need to take other essential documents with you as well. Bring your birth certificate and a photocopy of your passport number and driver's license in case your originals get lost or stolen. Put these copies in a safe place away from the originals to ensure that even if your originals get stolen, you will still have the copies. In addition, bring a list of your emergency contacts, your health insurance and your bank information. You may never need these, but you will be sorry if you don't have them if an emergency arises.
Even seasoned travelers get homesick. Choose a few personal items and mementos to bring with you like photographs, a favorite book or even a stuffed animal. Not only will these items provide a comforting reminder of home while you are away, they make great conversation pieces for your new friends. Your friends abroad will be curious about your home and family. Be careful not to take up too much room with personal items or you may overload yourself or end up having less room for things that you need.
Bring a few small gifts from your home state or country for friends and your host family. Each country has different rules and customs for gift-giving, so you should study the guidelines for giving gifts in your new country. However, almost everyone enjoys small items that represents your state or country like food, small clothing items or tasteful jewelry. One advantage of bringing these items is that you will be leaving them, which will free up additional room in your suitcase for souvenirs that you buy abroad.