Well written, technically, and quite readable.
It's not clear that you're going anywhere terribly
interesting, though. You might want to think of a
deeper hook for your readers. To expand a bit on this:
Ranma/SM crossovers are a dime a dozen. That does not
mean that yours _can't_, or _won't_ be interesting,
but it does mean that your potential readers need
something more to be persuaded to read _your_ story
(as opposed to one of the other half-a-dozen SM/Ranma
crossovers posted every week). You might offer:
1. An innovative setup or plot
2. Compellingly excellent execution
3. Humor
(One of my points here is that only a vanishingly
small audience will read this story _because_ you've
crossed over these two series. And, given your lack
of proper tags in your header, you won't reach most
of them. [See my header for example.])
You don't seem to fit into any of my three categories.
Your plot might indeed be very innovative, but I
can't yet tell (if so, let a few more hints get out
in the early stages).
Characterization seems okay, but not compelling or
vital. Your Nabiki is mildly interesting. Your
Ranma is not; I just don't care about him, and,
given where you seem to be going, I suspect I need
to.
Legend:
<thoughts>
(sidenotes)
_emphasis_
[panda signs]
*other languages*
//sound effects//
While in cursed form, Ranma=Ranma-chan,
Ryoga=P-chan, etc.
Ready? Good! Let's do it!
Some readers consider lists like this to be very
distracting. They're almost always unnecessary;
just introduce each convention with the appropriate
verb.