The only significant difference you really need to worry about when fitting a woman is that women tend to have shorter torsos. Keep an eye on that top tube length; you can always buy a longer seatpost, but there's a limit to how short you can make a stem.

Also, keep in mind that her posture has to be slightly different to rest on the saddle properly. Guys bend at the waist, women bend at the hips, so any pointers you have for posture for her should take that into account.