Some characteristics of a certain type of ineffective prose:
Abstraction. Often we don't know what the writer is talking about. There are abstract concepts, but nothing specific that we can put our finger on.
Self-Absorption. The writer seems more involved with herself than with the task of communicating, proud of her particular positions. A use of a lot of feel-good language masks the absence of justification.
Gratuitous melodrama or didacticism.. There is a sense of urgency or a call to action, but the writer cannot define what it is he really wants us to do.