I like structuring my paragraphs by what they represent semantically, like thesis, argument, example, idea etc.
Right now, it’s only possible to label entire files that contain multiple paragraphs. And, frankly, I don’t think it’s economically viable to create a file for every single paragraph (which can be as short as one sentence).
A possible solution would be: Assigning a (colored) label (or what-have-you) to a selected part of text, so like highlighting, but searchable. That would help me (and maybe many others, too?) a lot. That’s the single most important feature I wish Scrivener had.
Highlighting is already something you can search for, using the Edit/Find/Find by Formatting menu command. If you search the forum here for “tagging” or “keywording” text, you may find some interesting threads. My approach is to use inline annotations and simple text markers for stuff like this. I’ve posted some additional techniques as well as a method for automatically building lists of documents containing text marked in this fashion.
[size=85](Note most of those discussions refer to Mac menu names and keyboard shortcuts, but the basics should be the same.)[/size]