i think the first one would look better if you cropped it a bit to take out the unnecessary details in the background. your main subject is the lady, so you do not need a lot of other things in the picture, unless they add to the composition (in this case, they don't).
for the second picture, i would have used a smaller aperture to achieve a greater depth of field (higher f/ stop number). if you're not sure how to do that, the alternative is to make sure you focus on the dog's eye-the one in front so it pulls you into the picture.
i like the third one, but it is a little soft. were you using any type of filter-spot, fog, etc?
i think the photos are a good start. with some practice you'll be taking great photographs. =)