Good start, Accurender is a bit old, although I have seen some stuff from the new version coming out, so getting the quality that people expect these days may be difficult. The main two items are that too many surfaces are too shiny and some materials, the diffuse value seems like it is set up so high that scene lighting isn't really affecting them and giving any depth, the flowers would be an example of this in a way.
First image has a light source too strong and it is blowing out some of the color. Second image seems to have an unusual color pallet, pinks and purples and then a yellow carpet, I would adjust the carpet color. Third image has a very strong yellow light source which gives it an off look. Hopefully the comments are taken in the constructive fashion they were intended.