I can see you have done a nice composition here. I like it, there is something lacking though.
I can see you have read about composition or took art class, you have left a lot of empty space and place the three on the side. For some reason it does not work for me.
Perhaps the symmetrical foreground, water and background even though sometimes it works.
You should try to change the point of view, I mean keep your camera very high above your head and then shoot keeping the camera very low at your knees or lower.
The tree on the side is very good idea and commonly used technique to add dynamic to the photograph, unfortunately your tree is cut in half by horizon or the sky.
Great job though.