Many ESL teachers, especially if they’re native English speakers, make the mistake of preparing mentally for a lesson without actually writing out a plan. This can backfire in many ways: You don’t have a contingency plan for the lesson running short or long, or a different number of students arriving to the lesson. Questions or problems come up in the class, and you get stumped, which is more than a little embarrassing.

Determine your lesson objectives. If you’re using a textbook, review exactly what the unit or chapter will cover, for example: grammar, vocabulary or functional phrases. There should be a goal for your students to achieve in each lesson.

Think up a warm-up activity, to get students focused on English. This can be anything from recounting their last week's to topic-focused brainstorming. For example, if your objective is speaking about travel, have them work in small groups to think of countries they’ve visited.

Introduce the lesson's topic clearly. Using textbooks makes it easier, since they are written and laid out for this purpose. A textbook will usually have a lead-in such as a listening exercise to introduce a given chapter. If you don’t have a textbook, you can find professionally prepared lessons at different websites that you can use, or to use for inspiration (See Resources below.)

Include an exercise or activity that allows for practice of use, whether it’s vocabulary, grammar or pronunciation. You should then follow this up with guided practice through, for example, questionnaires, surveys or information exchanges. Reinforce the lessons learned through free practice like role-plays or conversation.

Allow time at the end of the lesson for revision or mistake correction. You can plan this by thinking about mistakes that might come up or identifying problem areas. For example, in a lesson on "Conditionals," it’s common for students to create sentences like: “If I had a hammer, I would …”

Give your students meaningful homework that is specifically focused on practicing what they’ve just learned. You can give an assignment from a workbook, handouts from a grammar book or essay writing.