How to go on a cruise
How I did it: Actually, my husband secretly planned the whole thing. Since he is a pilot, we got a discount on the trip. We did take a 4 day cruise during the end of October, so it wasn't the high season.
Lessons & tips: If you are active and want a lot to do, find a cruise that offers activities all the time. We found that the Carnival ship we were on lacked in that department. We pretty much felt like we were on a floating casino with all the lights (but without out the loud sounds).
Also remember that the price quoted will not include taxes and fees which may add up to over $100 a person!
Be aware that all alcohol and soda is not included in your price. The alcohol is expensive and you are charged a gratuity on anything that is charged to your cabin card!
The Carnival ship we were on charges $10 per person per day gratuity which is billed at the end of the trip. Also note that you will be expected to give your head waiter and cabin employees a tip at the end as well.
Just be sure you are aware of what it is you will have to pay for and budget that into your trip. Remember that if you drink, they add up quickly, so keep track of that too.
Resources: Call the cruise line you want to go with and ask every question. Researching online for each port we were at helped immensely.

