A structure like this one seems more focused on the ideas being compared and contrasted than on the comparison and contrast itself.
The similarities and differences between the ideas do not begin to emerge until the writer gets to the second idea.
You can, and probably do, use comparison and contrast to describe things, to define things, to analyze things, to make an argument -- to do, in fact, almost any kind of writing.
When they are comparing and contrasting, for example, two ideas, like corsets and footbinding, most writers structure their essays one of four ways. Writers using a comparison/contrast structure might begin by discussing the ways in which corsets are similar to footbinding, then they move to a description of the ways in which the two ideas are different.
This method is probably the one used most commonly.
A quick outline comparing and then contrasting corsets and footbinding shows one way that such a paper might be structured.
It is as if the writer is comparing and contrasting (for example) footbinding to corsetry, instead of corsetry and footbinding to each other.
Write only about the comparable and contrastable elements of each idea.
Depending on how organized your thoughts are, you might just jot out a few main ideas on a blank sheet of paper/computer screen or you might actually want to make up an actual list with columns for things the texts share and things they don't.
During this phase, just write down whatever comes to mind, no matter how miniscule you think it may be.