Assess the needs of your students. You may need to do this in their native language. Find out why and how the student will need to understand English. For example, one student may need to give presentations in English while another must travel to the United States for business.
Focus lessons on the things your students need to learn the most. A student who conducts business meetings in English will need to practice speaking and listening. However, if the student will only be communicating with clients via email, he'll need to work on his written grammar.
Boost industry-specific vocabulary. Each industry has words that are specific to that industry. For example, someone in the auto industry may need to learn the terms "powertrain" or "chassi." Research these types of words and create vocabulary lists that include them. These words are not likely to be in the textbook.
Start slow and build up. If your students speak little to no English, you'll need to start with simple introductions and other basic conversations before you move on to the types of real conversations that they are likely to have.
Offer role playing activities. Put your students in the types of situations they may encounter in business---taking an order, answering an inquiry, solving a problem, giving a presentation. This is another good opportunity to make your class unique to your students.