I like all types of travel. My experience with cruises have been very enjoyable. But here are some hints to make the trip better:
1. Be prepared for seasickness. If you are prone to it, get a prescription before leaving port.
2. Don't over-pack. Try to arrange your outfits so that you have mix and match sets. Depending on the cruise, you might need a formal outfit.
3. ALWAYS get off-ship at a port. Part of the fun of taking a cruise is the port-of-calls! Be prepared to spend extra money if you want to do the extras. But even if you just choose to explore on your own, you can still have fun.
4. Research your port-of-calls before departure. Have a sense of what you might like to see or do. Most stops are very short so it helps to plan in advance.
5. Put yourself out there. On board, if you are a wallflower you will be bored for most of your trip in a tiny little cabin. But if you throw yourself into different activities you just might have some fun and develop some friendships.
6. Enjoy food. Cruises are known for their constant overabundance of food, usually, fairly good food at that. You may want to take clothes with a bit more room in the waistline. But if you are not a foodie, or if you are a picky eater, much of the food experience will be lost on you.
7. Being a cabin steward is really a difficult life. Please treat them nicely and as LONDONER said, tip them nicely at the end of your trip.
If you do decide on taking a cruise, you will most likely have a very memorable experience. For all of the negative press these days, cruises can still be a great, and fairly economical way, to travel and to experience some new things. I hope that you both have a great time!