Thanks to all for compliments and critics.
you could be right: sometimes "killing" the background towards total blackness, makes the subject prominent.
But I agree that, being it blurred, does not distract much and can add something to the pic.
Tweaking can improve the original, but many would prefer the original with only a few sharpening on the subject and Noise reduction on the background.
Tweaking in these shots.
Isolate the background from the subject: in Photoshop "Selective colors" and then add or subtract selections and feather them.
If the background is uniform it's better to select it first.
Now apply Noise Reduction filter to the Background only.
With levels you can make th background disappear to total blackness or, with saturation, you can turn it more live or Black and withe.
In the last pic I applied a bit of "Paint daubs" Photoshop "artistic" filter.
After all this tweaking to the Background invert selection and so you have the main subject, the flower, selected: sharpening, a bit of saturation more if needed.
In the colored petals picture, I selected portions of the corona and changed the colors in Photoshop via "Hue - Saturation" command.
Lastly, always with selection and selections' subtractions, you can do frames around the subject.
Note that simple is betterin frames.
The one in the third pic might look complex but it isn't. When instead you make frames which contains patterns and colors, the distract from the centre of the picture.
After all it's all a matter of knowing tricks to select and knowing Photoshop/Elements/PSP functionalities.
As I often say, I tend to shot many pics with my FZ20 and WOW shots are obviously rare. But with Post Processing, you can turn good shots into "WoW" ones, making the subjects sharper, cleaning the sky from noise, improving colors, adding some blur to imitate DOF...