Over the years I've spent in business development, consulting, and client service, I've found somewhat consistently (albeit anecdotally) that using the right words within the proper context and with the right audience can help close a deal, save a project, or soothe a frustrated client. If the following words are active in your vocabulary - great. If they aren't - you may want to consider peppering more of your conversations with them:
What words are indispensable in your sales or lead nurturing process? What words have brought you the most success?