Teaching English in the U.S. and Abroad
Being an ESL teacher in the U.S. is a rather different experience than going abroad to teach English as a second language.
Teaching styles around the world vary greatly, from the more interactive American/Western European approach to monotonous lecturing, drilling, and reciting still commonly found in schools in the Middle East and Asia. If you are teaching abroad in the latter regions, or if you are teaching students in the U.S. from the latter regions, you can probably expect they will be passive learners in the classroom, waiting for you to do everything as they simply stare at you or take notes.
Regardless of where in the world you end up working, teaching in the ESL field is vastly different than teaching in any other field. You cannot assume anything about your students' background and culture. You must be patient and learn from them as they learn from you. You will eventually develop a teaching style, based on what seems to work for you and your students, which is why flexibility is key as an ESL teacher.
Just because your students might know a little bit of English and can usually understand you, you still should make a concentrated effort to speak more slowly and distinctly than you normally do. They will literally be hanging on your every word, and each word that comes out of your mouth might have an impact on the way they view and use the English language.
The main difference in TESL abroad is dealing with the culture shock and lifestyle changes you encounter on a daily basis. Practically speaking, you, as an American will have a hard time getting a job in the U.K. as an ESL teacher, as your students are immigrants who are trying to find work in the U.K. and need to hear and practice British English. As most ESL teaching is technically done in English-speaking countries, your adjustment period should (theoretically) be smoother than in a non-English speaking country where you don't know the native language.