Any suggestions as to how I can improve these pictures?
I agree with the other posters that the background could be improved. The image does look crunchy with poor gradation. Oversharpening might be involved. There is no clipping of the whites, but there is marked saturation clipping of the reds in the highlights and of blue and green in the shadows. The effect of the highlight red clipping is obvious, but the effects of the shadow saturation clipping are more subtle as explained
here (see How Levels works on color images). Shadow clipping of the non-reds removes those colors from the image, increasing saturation in the reds and possibly causing a color shift.
[attachment=18388:Amarylli...sto_sRGB.png]
The saturation clipping can be removed by converting the image to ProPhotoRGB, but the conversion can not recover data that have been clipped and permanently lost. Paradoxically, tere is no change in the appearance of the image when it is converted to ProPhotoRGB (afterall, the purpose of color management is to preserve the appearance of the image).
[attachment=18389:Amarylli...ProPhoto.png]
If you are working with raw files (and you should be in this case), render into ProPhotoRGB. This will likely avoid the saturation clipping. However, the resulting image will likely exceed the gamut of your output device (screen or printer) and you might want to decrease saturation a bit. I am not that experienced with this type of editing, and input from more experienced members would be welcome (Where are you Schewe and MarkDS?).
Bill