Something else to consider as well for your compositions is "natural" lighting. Looking through your renders, it almost seems they are getting progressively less realistic, at least in my opinion. Please don't be offended. Happens to me all the time.

There is a sample scene in VUE, consisting of two chairs, a coffee table, some plants, and a window. I would give you the file name but I am rendering something at the moment.

Take a look at the lighting setup for this scene. It's very well done. 

Consider using gels, soft lighting (by editing the shadow properties and dropping to 80% or so with maybe a .5 - 1.5 quality boost), reducing or eliminating object influence of certain lights as suggested, and just making sure it looks "right" to you.

As noted, the artist has to decide what is right, but it's a wonderful exercise to learn lighting, that's for sure!