RULE OF THIRDS
Frame your image with the subject off center it's more pleasing to the eye and appears more natural than placing the subject in the center.
The direction of attention in this photo is the butterfly and the flower. These two are the only things on focus as the depth of field is shallow, making the whole background completely blurred out. The lighting allows the bright color of the flower to contrast with the simple brown and black combination of the butterfly. emphasizing the two subjects.
This direction of attention goes towards Kathy, since she is at the center and the lines of the wall point towards her. The exposure of this photograph does not seem to be a problem. As for the focus, Kathy is at focus while the background is a little blurred, so the depth of field is appropriate. The light is also not a problem as there is no hard light shining upon Kathy's face. It is preferred to keep this photo in color rather than in black and white since the tone of this picture isn't serious or dramatic. I didn't apply the rule of thirds in this picture because the leading lines, added with the subject being centered, makes Kathy stand out the most.