Great start, but as Brickman said, the only real photos with a subject are the cat, bird, and leaf ones (maybe the second waterfall as well). The leaf has the end of it chopped off. It looks like you already understand how the Rule of Thirds works; but when you're about to press the shutter button, ask yourself, "is what is in focus well defined or outstanding enough from its surroundings in order for just anyone to easily pick out the subject?" If not, choose a subject - it changes the whole game (note that you don't really have a subject in landscape photography, and, while it may seem like it, none of those photos can actually be considered landscape photos).
Anyway, keep up the good work, you have awesome potential! :)
