Perhaps the most sensible tip is to arrive at the city nearest to your departure port a day or two ahead of time. This will give you enough time to recover from your flight, possibly enjoy the city itself, and not worry so much about getting to the boat before it leaves. You’ll also want to check and double check to be sure that you have the proper paperwork that you need to embark before you get to the gangplank.
When the boat is on the move, there are a number of things you can do to improve the quality of your stay. If you’re not a big fan of children or crowded spaces, check out the adults-only areas. These spots tend to be less crowded and less noisy than areas where families are welcome. If you don’t like making conversation with strangers, you might want to dine out while you’re in port rather than eat in the main dining area. Night owls might also want to check out the discos on board, even if that’s not normally their scene, since not much else happens on the boat after midnight. Also: check out this article as well as this one for even more tips.