Some examples:
When checking in, don't make guest fill up their email address again when this was already provided during the booking process. Don't ask for something you already know or have. If hotel would like to verify if same email is to be used, ask. "Mr. Brown, may I just confirm if your contact email is .....?"
When the spa receptionist was not aware that the arriving guest had already selected the type of treatment the previous day.
When guest requests for an item or service (e.g. hairbrush or to have turndown earlier), and is re-directed to another colleague/department without informing the other person what the request was about. At the very least, the second team member should be able to say, "Good afternoon (guest name), I understand you had a request regarding the cleaning of your room?" and not simply, "Yes, how can I help you?"
When diners had to inform the service staff they had already ordered the drinks when being offered yet again. Or that they won't be having desserts. Or not to clear the bread basket. Repeating and repeating to different team members who approach to ask the same thing.
When the guest requests via phone for some documents to be printed and sent to the room. The second employee does not need to call back to repeat exactly the same request that was being made, since this simple request had already been confirmed accurately by the first person. If deemed necessary, call to inform about something else (i.e. add value)- e.g. that the task has been slotted under the door as there was a Do Not Disturb sign.
In short, listen attentively, act intuitively and communicate seamlessly with other colleagues!