Month 10: Go Shopping!
I'm not a fan of old-timey corsets, but man did they get the job done. Tiny waistline? Check. Flat abs? Check. Supple, perky boobs? Check, check.
Fortunately, the undergarment industry has come a long way since the days of Scarlett O'Hara. Consider "changing" your body temporarily with a specially designed bra, compression garment or even just some control-top pantyhose. I even have a friend (who shall remain nameless) who wore underwear featuring a fake butt under her wedding gown. She wanted a little extra curve in her booty and the undies did not disappoint.
Whatever you wear, make sure to take your undergarments along for all alterations appointments because they obviously affect how your gown will fit.