What career opportunities are there with a master's degree in English?

Many colleges provide incredible teaching programs. A few of the best in the nation are Johns Hopkins University, NYU, and UConn

Teaching involves a number of different skills and qualities. I would say the most important are:

1. People skills - being friendly and working well with others. You will need to be personable, caring, kind, friendly, compassionate, and understanding. These qualities make a great teacher. But you also need to be stern and firm in your directions, rules, and discipline
2. Public speaking - every day in your class you will need to be able to speak and present information to your students, practice speech, and practice fluency of language and talking in front of others
3. The subject you plan to teach - become a master of the subject you plan to teach, make sure you know as much as possible and learn as much as you can about the subject you plan to teach. Take as many classes as possible in this subject and learn everything you can about it.
4. Psychology & Human Development - start reading books and research articles on human development and psych. It will be helpful for you to know how people learn at different stages and the best ways to teach them at these stages (depending on stage of development and schema).

With a Master's Degree in English you could become a college professor and teach english, an high school english teacher, you could become an author, and also work on sets of movies or television shows in the writing department. When I graduated I literally googles careers within my degree field, you'd be surprised the opportunities that show up.