The image is very flat (two-dimensional). This is mainly to do with a lack of tonal and focal differentiation, which are things that should work in harness to fill a good frame.
It's nothing to do with post processing in this case, it's to do with seeing the light and having an adequate vision before you press the button.
That's the gist of it, but if the highlights here aren't blown they're on the brink, and most serious of all the focus is wrong - it's on the leaves behind the flower when it should be somewhere in the flower's heart.
Let me guess - it was taken with a compact camera? Have you thought about a course, or some sort of mentoring?