Toni: The butlers do most anything you want. They will take your clothes to be cleaned or pressed. They will arrange your shore tours for you. They bring you afternoon tea and yes you tip them separately. Helen.
I'm probably NOT the guy to be answering this, but here goes anyway.
Theoretically, the butler will book your shore excursions, make reservations. Also, he will bring fresh fruit (of your choice) in the morning and hors d'oeuvres in the evening. That's what he's supposed to do.
My experience was that our butler did none of these things. Rather, it was passed on to the cabin steward. I know my experience here is probably singular as others have raved about the butler service in the mini-suites. Alas, this wasn't the case with me.
One is supposed to tip the butler per day as one would with the steward or waiter, etc.
I'm going back on the Grand in January and have again booked a mini suite. I'm hoping for the best.
It's truly a wonderful ship and the butler service was the only drawback. You'll have a great time.
Depending on when exactly you are cruising on Princess, read recently that sometime in the near future they are discontinuing this service. Forgot the dates and they didn't state the reason why. Hope you can enjoy the service before its no longer, have a great cruise!