Ignore whoever gave that advice about cogs and dirty and all of that crap. That is NOT what steampunk is, and steampunk should not be limited to that. Cogs have gotten to the point where they're unoriginal and generally serve to look contrived. Steampunk is so much more than cogs and brown and all that BS. What you want to do for this particular costume is go for a more Neo-Victorian-esque theme.
I would suggest pink and white spats, in the colors that Sailormoon uses. Use high-buttons on the side of them. You can also go for a theme like Princess Sailormoon from the liveaction PGSM has (a lace petticoat underneath the skirt). I would say to stay FAR AWAY from the brown underbust corset. If anything, what you need is a better quality corset than what you are wearing in that picture - a white overbust with steel boning. You can then do what you wish with it.
The collar should be retained. I'm not particularly fond of the way that collar looks because the braiding looks cheap.
Everything else looks fine to me.