Modeling is it's own particular art form. From what I have seen, there are principles that are common to most modeling softwares, once you familiarise yourself with the interface. What Carrara seems to be is a fusion of several different features. I confess that as a previous user of RDD 5.0 It took me a while to properly familiarise myself with the interface, but many of its properties are strongly shaped by its heritage as an outgrowth or the RayDream family. Any manuals or Quickstart guides for Ray Dream studio will give you a good deal of background.