When a bride comes to me for a gown and is a little lost as to where to start, I suggest she think of a style of dress that she already knows fits and flatters her. For some women this give them a jumping off point!
The skirt, train and veil all combine to say wedding gown the bodice and sleeves, (or no sleeves etc.), are where most of the comfort lies.
I feel the woman who is comfortable in her gown and doesn't want to take it off at the fitting - she has the right gown!