On an Aristotelian account of practical reasoning, practical reasoning necessarily has an analogy to theoretical or speculative reasoning; the difference between theoretical reason and practical reason is only one of mode. Thus one represents practical reason syllogically.
MAJOR PREMISE: Everyone in these conditions should take a walk.
MINOR PREMISE: I am in these conditions.
CONCLUSION: <the action of taking a walk>
Aristotle always presents the major of a practical syllogism as having a kind of relative necessity (what must be done, what should be done, what is needed); this is analogous to the major in a theoretical syllogism having a greater universality than the minor. He is also very clear that it concerns a good or end, and that it does even if it is not immediately obvious that it does. Thus we should see the major as identifying a requirement for some good or end in view, where the actual good may be explicit or just implied.
The minor, then, concerns my relevance to the requirement, including my ability to fulfil it. Thus it generally concerns the achievability of the end presented in the major, or, in other words, the possible means to reach it. (Although you can have a minor concerned with the means being lacking in some way.) This results in one of the ways in which the practical syllogism definitely differs from the theoretical syllogism; since the major does not have to apply to me in only one way, the minor does not necessarily exclude the opposing minor; the minor is put forward not because it is true but it is positing something so that something else will be made true. We have power over what we can do, so the minor premise in the practical syllogism is often not the only one we could use. Therefore, while the theoretical syllogism is a syllogism whose purpose requires it to be truth-preserving, the practical syllogism is a syllogism whose purpose is concerned with truth-enacting.
A second difference between the practical syllogism and the theoretical syllogism is that the conclusion of the practical syllogism is actually doing the deed. There is a school of thought that holds that this was a mistake -- that there is reason why we should treat the conclusion of the practical syllogism as distinct from the action itself, and therefore that there should be a distinct 'practical step' between the two. This is, I think, a mistake -- it's analogous, in fact, to the mistake in holding that there needs to be a 'step' of representative ideas between what we see and the world, in which we perceive representative ideas rather than things represented. It also over-assimilates the practical syllogism to the theoretical syllogism, by treating it as nothing but a theoretical syllogism about practice. Instead, the practical syllogism is itself practical, and the conclusion is not something known but something done. Thus the last judgment in practical reasoning is that which is expressed in the action itself. Actions, after all, cannot be wholly separate from the acts of the practical intellect, which they would be if they were separated from its conclusions. When, given an end, we act at once, this is the practical syllogism equivalent of the enthymeme.
We deliberate by means of the practical syllogism, and deliberation often goes wrong, Aristotle says, from faulty middle terms in the practical syllogism; but deliberation is not itself the practical syllogism. Rather, deliberation is related to the practical syllogism something as dialectical reasoning is to the theoretical syllogism; the practical syllogism is something we construct in deliberation, by deliberation. To be rational, of course, it requires a standard. Theoretical or speculative syllogisms, which are constructed in inquiry in order to know the truth of something, are measured by soundness -- truth in a structure appropriate to it. Practical syllogisms also have to have such a standard, but being constructed in deliberation in order to do something, the measure would have to be something like prudentness, i.e., a structure of means appropriate to an end for action.