Originally picture was quite boring because of absence of some bigger contrast.
To improve that I rendered omni lighting to the place behind the flower:
Then I added adjustment layer Levels above the background layer and do the scene lighter. Then I filled the vector mask with black and painted with soft round white brush with low opacity over the areas which I wanted to have lighter.
Then I added new layer, fill it with black and add lens flare. I changed the blending mode on Screen and lower the opacity on about 20%
During the next step I added adjustment layer Levels on the top of all layers and set it to very light colors. Filled the vector mask with black and than painted with white brush over the areas which should be higlighted.
Then I did the same with shadows:
After that I added vignette. I added adjustment layer levels, set it to darker image, filled vector mask with black and painted over the corners with white brush.
The last thin I did was that I added grunge texture, set the blending mode on Overlay and lowerd the oppacity on about 20%. It increased contrast a little.
If you have any question just ask me.