Taking a cab from the airport will be the most direct. If you arrive early, be prepared for a wait. Usually if you arrive mid afternoon, the waits are less. Have your luggage properly tagged with your name, cabin number. I like putting 2 tags on, consider it in case one gets pulled off. Tip the porters.
Have all your documents filled out and passport/ birth certificates handy. Take the map of the ship with you from a cruise brochure, the ship maps on the ship are lacking usually.
Have a great time.