A teacher needs not only a requisite knowledge of how the English language works and how to teach the four skills: reading, speaking, writing, and listening(The Practice of English Language Teaching by Jeremy Harmer is one of the most comprehensive books in the subject) but also a suitable awareness of the various teaching methods and principles that are or were employed.
For a practical synopsis of these trends and methodologies as well as an explanation of how they are applied in the classroom, Techniques and Principles in Language Teaching by Diane Larsen-Freeman is an established reference.
A teacher's job involves much more than just preparing a lesson plan. This is only part of what a teacher has to do on a daily basis. If you are endeavoring to become successful, you need to be an expert on how to manage your students and keep them focused and motivated, on how to deal with problem students, on how to get along with your colleagues, the school administration, the parents, etc...
Although some of these skills come with time and experience, one interesting book that tries to provide answers to all the matters mentioned above and more is
The Unauthorized Teacher’s Survival Guide by Jack Warner and Clyde Bryan, with Diane Warner
It is a must-read for every wannabe successful teacher.
In coming posts, I will write about some of the tips that the book offers to us. However, to fully take advantage of the book, consider buying it. It is worth every penny!
That is, in my view, a great place to start with. I do not claim that other books are less important or less comprehensive. I really hope other colleagues will suggest their own list of good references and tips.