craftgrrl | refitting dress shirts.

I wasn't able to find this specifically in the FAQ/memories section, so I hope you guys can either help me out or point me somewhere that can:

I just bought a couple women's front-button dress shirts (or "blouses" if you will) online. I bought them a bit too big on accident and I need to take them in, but i'm not really sure how to do that.

They're supposed to be for work, or else I'd just use ragged sewing/cutting and safety pins and make them look punk rock or something.

They are also slightly fitted and I want to keep them that way.

I don't really know where I should start and if I should take it in at the sides or at the back or what.

thanks!