We like to get balcony rooms midship (less motion), on the port side (left side). It depends on your itinerary (ports). and how the ship is docked, or moored. In our experience the best is port.
~~~ MY opinion only~~~
We had adventures in Skagway, and again in Hawaii, which we got to photograph because of a portside cabin.
I also prefer to use a TA because she takes care of everything!!!
And~~she gives us nice onboard gifts.