Welcome aboard. It is nice to see new faces. I apologize that no one has answered your e-mail. The three images are a good start, but do have some issues that I think you will be able to improve on quickly.
Let's first start with the red tree. This image of a pretty tree is having some difficulty with dynamic range (the ability of the sensor to capture both brightness and shadows). Digital cameras have been said to be similar to slide film in how they can capture data...specifically that they cannot capture as much as print film. The flowers at the tip of the tree appear to be losing detail as a result, while the leaves at the bottom appear to be silhouetting. The image looks like it was taken in when the sun is at it's peak, which I believe is causing much of this problem. i.e. had you taken the shot at a time when the sun's light was coming at a different angle, the tree would have been more evenly lit. The second thing about this photo of the tree are the background items, like the cars. I think that they detract a bit from the subject of the image.
The two other shots you showed of the white tree have stronger compositions. I could not open them up large enough in the server you are using to really check out detail in either of them. The trick with these again has to do with exposure. The second image is a little bit under-exposed, as I feel the camera tried to meter from the sky. The 3rd image is clipping at the edge of the tree, and appears a little bit under exposed throughout.
Again, Adam, welcome aboard. I hope that my answers are helpful to you.
PS We are normally all glad to help and review images. You might want to try posting one at a time as I think folks are more likely to answer.