Hmm...not bad, for a first try. However, two things strike me in
particular:
1. Ranma-is-a-relative-of-the-SM-cast has been done. To death.
Repeatedly. Ad nauseous ("until nauseous"). True, he's usually a
relative of Usagi or Rei, but moving this relationship to one of the
Outers doesn't change much. (Now, if you want to have Ranma following
and bunking with Haruka, making her one of his former senseis - a
nonprofessional sensei, but still one he learned some tricks from -
might work much better. This might work for Makoto too.)
2. Remember to put " on both sides of any speech or thoughts. For
example:
A raised eyebrow was her only visible response, though
she thought, the place where freighters dock, that must
be at least 35 or so kilometers away as the crow flies."
This looks very choppy, until on realizes that there should be a "
between "thought" and "the".