Speak only English in the classroom. It is extremely important to focus on getting the students comfortable with English. When the students begin to speak in their native language, you should gently direct the conversation back to English.
Encourage as much inclusive participation as possible. All students in an ESL classroom should be involved, otherwise some students can easily and quickly fall behind.
Provide as many concrete examples as possible when teaching abstract concepts. For example, when teaching a principle of grammar to an ESL student, give examples of how the principle is used in actual conversation.
Focus on the students' needs and adjust the content accordingly. If students don't understand a complex principle, the ESL teacher should attempt to break down the principle in easy to understand components.
Allow students ample time to answer a question. Never interrupt an ESL student's thought process. It may take him significantly longer to formulate and express an answer.
Don't slow down your speech for the students; speak at a normal rate. This will help them in the long run to understand conversational English.
Review key concepts at the beginning and end of every lesson. Reinforcing information is important for ESL students.