We thoroughly enjoyed our time aboard the Grand Princess. Here are some tips that we hope will be helpful!
Standard balcony rooms on Caribe (deck 10) are twice as deep as others! And they are private; you can be under the overhang where no one can see you or out in the sun.
If you are planning on shopping, go to the shopping talk and sit up front, close to an aisle. Pick up the Port Shopping Guide ($25) and you get ALL kinds of free stuff (including jewelry!).