Introduce yourself with first name and surname and give the reason for your call.
"This is Thomas Müller form Munich, I'm calling about our appointment next week"
Wait for the reaction of your speaker. He may usually be the one who takes the initiative to call each other with first names.
If you have been surprised by a call, you should find time to prepare yourself:
"Sorry, could I call you back in 15 minutes? I'm in a meeting at the moment"
Nobody can object to this.
If you haven't understood something, politely ask the speaker to repeat.
It is recommended to do so straight away.
"I'm sorry, I didn't catch that"
"Could you speak a little more slowly, please?"
There are some expressions you can use to show that it is your turn:
"That's a very interesting point, but..."
"If I could add something here..."
"Could I comment on that?"
Use polite expressions such as "I'd like to..."; avoid saying "I want..."
"Could" and "would" are important as well:
"Could you send me your latest catalogue, please?"
"Would you like to meet next week?"
Sum up briefly what has been said to make sure that you and your speaker are talking about the same topic:
"So what you're saying is..."
"If I understood you correctly, you're saying that..."
Some expressions can help you during your phone call. Write them on a sheet you place near your phone:
"I'd like to leave a message for Mr. Smith"
"Can we arrange an appointment for Thursday?"
"Let me check my diary"
"I look forward to seeing you next week"
You can compare the end of your conversation with a plane's landing happening over several steps:
"Thank you very much...that was very helpful...it was nice talking to you...I look forward to seeing you next week...bye"