Unwanted attention can range from a mild nuisance to a serious threat of danger. Acceptable treatment of women in your host country may be very different from the kind of treatment acceptable in the United States. Also, the way women interact with men in the United States may not be as socially acceptable in other countries. What's considered "being friendly" in the United States can be considered flirting or a sexual invitation in other countries. Even reacting (positively or negatively) to unwanted attention can serve to egg the other person on. Personal space and boundaries may also be different in other countries, so make sure to clearly establish behavior that shows you are not interested.
In television and movies, the media tends to portray U.S. women as promiscuous. Simply smiling or saying hello to the opposite sex may be all that is needed to confirm this unflattering stereotype in their minds. To avoid trouble and unwanted attention, ask local women you meet and your program's administrators about what is considered "appropriate" behavior and dress for women. Dressing conservatively and traveling in groups are always safe bets. Although it is important to learn to adapt to a foreign culture, that doesn't mean you should have to compromise your own sense of security and dignity. If you feel you can't adapt to your host country's sexual culture, you may have to be more selective about the location of your program. Some female students, in certain overseas locations (e.g., South America, the Middle East and parts of Europe) have a hard time adjusting to attitudes they encounter abroad, in both public and private interactions between men and women. Some (but not all) men in such countries openly demonstrate their appraisal of women in ways that many American women find offensive. It is not uncommon to be honked at, stared at, verbally and loudly appraised, and to be actively noticed simply for being an American woman. Sometimes the attention can be flattering. However, it may become very annoying, and potentially even angering. Indigenous women, who often get the same sort of treatment, have been taught how to ignore this attention. Many American women students find this hard to do. Eye contact between strangers or a smile at someone passing in the street, which is common in the U.S., may result in totally unexpected invitations. Some women feel they are forced to stare intently at the ground while they walk down the street.
You will have to learn what the unwritten rules are about what you can and cannot do abroad. Women can provide support for each other, and former students suggest that you get together several times early in your stay overseas to talk about what works and what doesn't for dealing with unwanted attention. American women are seen as "liberated" in many ways, and sometimes the cultural misunderstandings that come out of this image can lead to difficult and unpleasant experiences.
Needless to say, this special and surprising status may make male-female relationships more difficult to develop. Be careful about the implicit messages you may be unintentionally communicating. Above all, try to maintain the perspective that these challenging, and sometimes difficult, experiences are part of the growth of cultural understanding which is one of the important reasons you are studying abroad. Prepare yourself by trying to understand in advance not only the gender roles and assumptions which may prevail elsewhere, but also the uniqueness of American gender politics, which may or may not be understood, much less prevail, in other countries.