International Business English

Confidence is an integral part of business dealings, and can be gained not only through improving your listening skills and conversational English, but also by knowing more about your own culture, and the culture of those you will be interacting with.  Misunderstandings can be avoided through researching the cultural norms of the person or people with whom you have business.
An extremely helpful website I use as a resource with students is the following:
http://geert-hofstede.com/countries.html
This site allows you to compare your own country to other countries, looking at things like the distribution of power between classes within a society, levels of individualism, and more.
Knowledge is power, and the more you know about other people and yourself, the more easily your business transactions will flow.

I also like to use books like Market Leader from Pearson and Longman.  There are many other resources that can be used in lessons, and of course individual needs are always considered and investigated through personal research on my part.