1. Do remember that in the afternoon one hour is devoted to lunch and prayer. Don't schedule your meetings around this time, as this is impolite.
2. Add some extra time while scheduling business meetings when you're in Iran, as people of Iran are a little relaxed about time.
3. Always remember that Iran is a Muslim country therefore, take care of prayer timings and special occasions like Ramadan and Friday, while making an appointment.
4. People of Iran negotiate a lot while doing business. Keep this in mind when you're in Iran.
5. Wait for women to offer their hand for a handshake or to initiate a conversation. Not doing so is considered impolite there.