The notion of "normativity" refers us to the nature of norms in reasoning. Norms are standards that are aimed at in an activity. For instance, in the general theory of rationality, we describe the standards of consistency and non-contradiction as essential prerequisites in how we think and thinking that does not obey such standards is, by virtue of this, taken to be irrational.
Similarly, in prudential judgement there is a basic norm that refers to one's interests and which further highlights which interests are to be taken as paramount. This reference, again, makes apparent the basic line that cannot be crossed if one's actions are to meet the criteria of prudence and if it is crossed then one faces the judgment of being imprudent.
From the recent postings one thing that becomes apparent is that there are normative considerations at work in any type of hypothetical imperative. Following the discussion of Korsgaard, however, it also appears reasonable to state that there is something normative at work in instinctive action where that action is action that is guided by a norm of appropriateness.
The key area of normativity is in the region of morals and part of the basic dispute when it comes to the region of practical reason concerns the reason for taking some norm as basic to morals. The attempt to defuse the appeal to contrary "values" is at is issue in the Kantian formalist approach to ethics as this approach moves away from the contested areas towards a "procedure" or "method" that is meant rather to test for what can be taken to be valuable (notably, in relation to questions of consistency as we indicated above occurs in the general theory of rationality).
Instrumental and rational requirements have to be related if there is to something like a general theory of practical reason, a theory that can determine the specific province of morality in relation to other normative requirements. The nature and scope of disputes in the area of practical reason turns precisely on how the relationship between instrumental and rational requirements should be understood, something that thus requires a general theory of normative justification. The provision of the preconditions of such a theory can thus be broadly seen but how to fill out the detail is the basis of the discussion that is currently central to the disputes between Kantians and others.