The best tip I can think of is learn how your camera works and learn about your medium itself.
Seriously >>;
There are so many people out there that just pick up the camera, press the button and expect magic to happen. I was guilty of this too! sweatdrop Just by learning how to work exposure, etc, your photographs will improve immensely.
Other than the obvious, there are two tips that I would put tied as the best? Go out of the box and always bring your camera with you. They're both equally important in my opinion.
As for the first, don't take photos head on, move around and see things from other perspectives! There have been countless times where I'm rolling around on the floor, trying to get a different view of something. Just about every time I've done that, I get a better picture!
And as for the bringing your camera with you, moments happen all the time that a camera could capture.
Hope that helps!