Have a martini at the Piano bar.
Try all the restaurants. Especially 8 Rivers.
Don't be scared to ask for something new at the bar.
Try a Bob Marley (on a side note, it is not my favorite, but tradition demands at least one).
If you have any thoughts about the Island, try it the first day. If you don't like it you can always leave, but if you do like it, you don't want to be kicking yourself for not going sooner.
Try as many new drinks as possible. I saw in the piano bar that they had a bunch of varieties of Pucker, so I just went down the line trying flavored martinis. I now know that I LOVE cherry martinis made with Grey Goose and cherry pucker. Too many many bars in the USA don't stock cherry pucker!
Order as many entrees as you want in the restaurants :-) I couldn't decide between two at Bayside, so I had them both. They're not super-huge portions, but I love to eat!
Get a massage, soooo wonderful. Also, in the evening, the hot tubs by the spa are open to both genders (during the day, they are separated by gender) and were empty when we went. Super romantic, and very private if there's no one else there.
Go on an excursion or two. I loved our vacation at CTI, but we were there for 7 days and did get slightly bored. We only did the included Dunns River Falls and Catamaran Cruise, but should have sprung for at least one more excursion just to break up the time spent drinking and reading on the beach.
You MUST go to the SPA and enjoy all that they have to offer! Bayside was my favorite restaurant by far, they have such a wonderful ambiance.
Have them make you a Jamaican Smile. If you have the opportunity to upgrade to a one bedroom suite GO FOR IT! I walked around for the first hour just saying WOW! over and over. Then woke up the forst morning doing the same thing.
If you have a lightening storm sit on the balcony and enjoy it. What am amazing show of nature.
Take the time to walk around the property and take in everything.
Try your best to HIDE when the sad bus shows up to take you back to the airport!