Be sure your interpreter is well versed in your business and understands the goals and objectives of the meeting or presentation.  AND, always hire the best--your business depends on it.

If you are making a speech or presentation, be sure your interpreter has copy of the text in advance.  Explain important and/or difficult concepts and points. 

Use your own interpreter whenever possible.  Using your counterpart's interpreters is a distinct disadvantage.

Depending on the language, interpretations may take much longer than the original.  For example, most people find that when translating from English to Japanese, the Japanese translation is about twice as long.

Speak clearly and slowly.

Pause after about 60 seconds, after a thought is complete (if not too long), or after major points have been made.

Watch your interpreter to be sure he/she is keeping up with you.

Avoid long, complex sentences, and do not use slang, jargon, or colloquial expressions.

Avoid jokes and humorous stories.  Humor does not travel well.

Advise your group that only one person should speak at a time.