Teaching beginners can be frustrating, especially if you don't speak your students' native language. Pictures are by far the best way to get around this hurdle. Bring in pictures for every new word. Introduce new grammar concepts using time lines. Get the students involved by playing memory games with the pictures: scavenger hunts, flashcard games and team activities are also useful. Encourage them to create simple stories using the new vocabulary. For example, if you're introducing food words, have them talk about their likes/dislikes. "I like oranges but I don't like apples..."
Intermediate students have grasped the concept of the basic tenses, and they know enough vocabulary to portray many thoughts and feelings. Often, however, they're not confident and don't utilize their full knowledge. Guided activities help them gain confidence. Debates are especially useful, because they get the students to talk about personal opinion. Bring in a simple article on a contentious topic (make sure to be aware of the country and cultural attitudes and plan accordingly), have them read it and then introduce appropriate functional language to help them speak, such as, "In my opinion...," "I respect your views; however..." or "I think..."
Advanced students can read most authentic resources with no difficulty, and can understand spoken English at a near-native level. However, gaps in basic knowledge can occur, and most students will struggle with one problem area. A student may be able to read anything, but have trouble understanding spoken English. At this level, encourage them to speak by introducing personalized topics they're interested in. Before reading or listening to the authentic material, preteach any unknown vocabulary (usually more esoteric words). Afterward, encourage discussion using this target language.
Every level loves games. Learning can be as stressful as teaching, as students may feel adrift in a sea of incomprehensibility. Team games introduce a spirit of camaraderie and enjoyment to the lesson. Hangman is always a good choice and a fun activity if you have five minutes at the end of a class to fill. For any level, you can write several topics on the board: "Jobs," "Vehicles" or "Emotions," graded to your students level. In groups, have them find as many words relating to the topics as possible before time runs out. The group with the most words wins.
Role-plays, where you introduce a certain pretend situation and then have students speak as though they were in this situation, is a useful way to get any level to speak. It's good for practicing practical situations: going to the doctor, having a car break down or being introduced at a business conference. You need to give them a format to follow. For example, if the role-play is "Going to the Doctor's Office," then divide them up into groups of two, one to be the doctor and one to be the patient. Give them sample phrases to say: "What seems to be the matter?" "My stomach hurts" or "I think my ankle is broken." Have them act out the movements by patting their stomach or pointing at their ankle. Make sure they switch so each partner gets to practice all of the vocabulary.
For intermediate and advanced students, you can introduce freer role-plays. For example, one person could be the parent, and another a rebellious teenager who wants to attend a rock concert. Always give students target vocabulary you want them to use.