Those bright spots are glare (a direct reflection of the light source). There is also some glare on the leaves. All of the glare combined is a very, very small part of the image. Even so, minimizing or eliminating the glare would have made the image even nicer than it already is because everywhere you remove glare you display more detail. A polarizer would have minimized the glare but its doubtful that all glare could have been eliminated using only natural light.
Consider adding a slight vignette, perhaps so slight that you wouldn't notice it until you remove it.