First off the first time ever being on a ship can be a pain. They seem like huge floating cities to my girlfriend and she does get a little lost without me sometimes but always makes it to where she was intending with a few tips.
-Any time on a Royal Caribbean ship you will sometimes see models of the ship onboard, those ships will ALWAYS face the same direction and the front of the model ship will be pointed towards the front of the ship. The same often goes for deck maps and such.
Most of the ships now have touch screens near the elevators on each floor that will allow you to get help and make your way around. Use them as they are each programmed with their location and will give pretty good directions to get around if you are unsure.
Remember that you CAN often make it to another elevator bank instead of waiting. When shows are released the elevators are often packed and busy, this includes port days. But often only one of the elevator groups will be busy but if you walk towards another part of the ship you can catch an elevator with minimal waiting even if the other bank of elevators is literally packed with people waiting. For instance when a show releases the elevators nearby will be packed but you can often walk along the ship to another set of elevators to use.
Try to use the elevators for going up more than 2 floors only. I know some people have a difficult time walking and that is fine but if you are going up one or two floors consider taking the stairs and every chance you can use the stairs to go down. Again this is more for those people who do not want to wait.
If you have just gotten out of a show and do not want to walk through the casino (and all the smoke) go out onto the deck instead. Many of the ships have an area outside on the same deck as the casino that you can walk along easily to navigate towards the rear of the ship. This is highly useful when a large show has released. For instance on Freedom or Voyager class ships when leave the theater I come out on deck 3 and take the stairs to deck 4 and then walk along the outside deck and avoid the casino to head to the rear elevators. Doing this I can often beat others who walk through the casino and will beat most of the people waiting for an elevator on deck 3.
Study the deck maps before you even get on the ship. Seriously, look them up or grab the RCCL app on your phone or tablet and figure out the location of your room as well as the location of major area's. Worst case if you are getting confused you can generally find a way to get to area's where someone working will be able to help get you pointed where you need to go.
And if someone starts talking about bow, stern, port, starboard, fore, aft and amidships remember this.
Fore = forward or front of the ship. The front is also where the bow is located.
Aft = afterward or rear of the ship. The rear is also where the stern is located.
Port = the left side of the ship when facing the front or fore of the ship.
Starboard = the right of the ship when facing the front or fore of the ship.
Amidships = the middle of the ship. So if you are in the middle you are amid ship.