Well, you might want to consider a polarizing filter. Do a search on this website and others to see examples. They are essentially like polarizing sunglasses. They bring out the blue in the sky and help to avoid your photos from getting washed out (sky turning white under bright conditions, etc.) and they help to eliminate or reduce glare off the water (which is one of the main reasons people buy them). I've never actually used one seriously, so technique is beyond my knowledge, but I've seen incredible results. The cheap ones are twenty bucks and the good ones are (I think) about $150.
Some people also like to use neutral density filters (ND filters) for bright conditions in which you are taking pictures of landscapes. There is a thread on here for that as well.
A tripod is always a good thing to have. But traveling with one is annoying unless you buy one that folds very small or have a table-top tripod. It helps a lot when taking landscape photos.
Read the owner's manual on your camera thoroughly so that you understand exposure compensation, aperture, etc.
Generally, if you are shooting quickly moving objects you might want to use TV mode and set your shutter speed to 1/400 or higher.
If you want to shoot portraits with the pretty blurred background, shoot AV mode and keep the number as low as possible. The more distance between your subject and the background, the more background blur you can achieve (bokeh).
On the other hand, if you want everything in focus, such as the palm tree right in front of you AND the sailboat a mile out to sea, use AV again and dial in higher numbers like 11-18.
Keep in mind I'm giving very general numbers because each situation is different.
When shooting landscapes, always keep your horizon as level as possible.
Also, if you are shooting people within fifteen feet of you (give or take a few feet) and the background is bright, use your flash. Daytime flash is invaluable and gets really good results.
For nightime you'll have to ask someone else. I stink at low-light photography.
Finally, auto ISO works really well on Canons and auto white balance works well too. If you really want shots that you'll treasure for a lifetime, shoot Raw + jpeg. You'll be glad you did.
Have a great time, and beware of counterfeit Cuban cigars. 
Thank you. 