Hi Ingrid,
Welcome to the group! This is a good photo. I enjoyed viewing your PBase galleries.
One key to creating portraits is paying attention to the background (horizon is at eye level) and in this case the grass the dog is in. I would also like to see some more light on the dogs face, to put a sparkle in his/her eyes. I also find having my camera and lens slightly higher than the subject gives a better result. Not standing looking down, but not at eye level either.
In your galleries I am not sure what the protocol would be for using flash, but if you can use flash on these more portrait type of photos, I would recommend it. Just use it on low power so it is not obvious.
Working on this image in photoshop or other editing software could really enhance an already nice photo.
You are off to a good start, I look forward to seeing more of your work. I hope this is what you were looking for in regards to comments.