I recommend visiting http://www.reddit.com/r/ABraThatFits/. They have helpful measuring and shape guides and tons of information about what bras work with different shapes. Using their guide I went from a unflattering 34 DD to between a 30 F to a 28 G. Sounds crazy, but it is true. Transformed my relationship with my chest and with bras. AND I look smaller and Perkier which, at 50, is welcome!

I would go to an independent bra shop that carries 1 of all sizes or can order that as opposed to a large dept store that has to buy 6 of one size, 10 of another, etc

I was sized in an independent shop and cannot emphasize how great these bras are. Pricey, yes but in my 35 years of bra wearing, I have never had such great bras. For once, I don't hunch over trying to hide my breasts.