Improve what part of it? If you want to make her more comfortable on it, simple things like bark busters can do wonders. Barkbusters can inspire a little confidence in newer riders (I don't know her skills or abilities) because it will make them feel safer by protecting the hands from sticks, brush, and trees. They don't feel so exposed. Did wonders for my girlfriend. If you have them and she doesn't...
If you want performance, hit up your favorite search provider for sure. You can re-gear it, install new exhaust (supposed to do wonders for the 230), port the head, de-dingleberry it (sounds like there was a lot of extra casting material left in the exhaust ports or head). Open the air box up. Jetting.
How far do you want to go? Big bore kit?