Probably the best tip I can give you is to come fully prepared with all the film, memory cards, batteries, charger ... you can muster. Bring twice as much film or memory cards as you think you will need. There are endless opportunities for incredible pictures, and you should be equipped with as much film ... or close to it. When your memory card is full, or roll of film complete, take it out of your camera and put it in a safe place. If your camera is lost, your precious photos will still make it home. Don’t be afraid to take too many pictures; digital cameras have not only taken much of the guesswork out of whether or not you captured the shot you were hoping for, but they also allow you to make multiple attempts without sacrificing valuable film. 45 pictures of a Galapagos tortoise? No problem. Delete the 35 blurry or botched shots and save those top ten gems.
Get down and get in close
Instead of towering over your subject, get down to their level. Even if your subject is not looking directly into the camera, this eye-level view really personalizes the picture.
Move the subject from the middle
The subject does not need to be centered in the middle of your picture. Framing your picture off-centered will add extra interest to your picture.
Shadows and light
Be aware of shadows and light. Shadows hiding a smiling face is one of the quickest ways to spoil a fantastic picture. Using a flash outdoors can help eliminate or soften shadows. Remember, there is little substitute for natural light. Take advantage of it whenever possible.
Anticipate the shot
Unfortunately, many digital cameras still have a slight delay. For action shots, try and anticipate the movement and snap your picture a moment ahead of schedule.
Experiment with your camera
Every camera is a little different, and some of its features might surprise you. Still not sure what that palm-tree icon does on your camera? Wondering if your camera has a panoramic setting? Trying to figure if you should use your flash at sunset? The only way to find these answers is to take the time to really get to know what your camera can do for you before your adventure begins.
Go for less "cheese" and more candid. Candid pictures commonly capture the moment better than even the best of posed pictures.
Vertical or horizontal?
It is very common to get caught-up in taking only horizontal pictures, but make a conscious effort to turn your camera the other way and take a few vertical shots. You'll be surprised how this simple change can really enhance and transform an image.
This is particularly important if you are taking pictures of wildlife. While it's true, a sea lion can remain sluggish on the beach for hours, they will give you some great action shots eventually. And when the action starts -- start shooting and shoot, shoot, shoot. Delete the duds later.