Make sure you know about and have the proper documentation for your cruise with in 60 days before your tip. This will give you time to order a passport or a birth certificate.
When you board the ship, spend some time the first day exploring and finding your way around. This will make it easier later when finding the dining room for dinner or the casino for a little action.
Every sailing will have a lifeboat drill or otherwise known as a Muster Drill. that is Muster not Mustard. These are required my maritime law so you MUST ATTEND. Some cruise lines require you bring you life vest which are in your cabin and some don't. Simply follow the instructions of the captain. You will be given a time, usually an hour or so before departure.
And remember, the ship cannot leave port until everyone has attended the drill.
Take the Stairs
Taking the stairs if possible is crucial in being comfortable and better for time as well. You will eat so much during your cruise so the stairs will help burn off some of those calories.
Also, the elevators can be slow on embarkation days and at busy times on the ship so why wait for an elevator and climb to the fun.