In Caroline Weber's Queen of Fashion: What Marie Antoinette Wore to the Revolution, she discusses the time period when Antoinette refused to wear a stifling corset, and later on she of course went for more comfortable wear. Wearing pieces that you feel comfortable in are key. Sometimes belts or ribbon will accessorize and offer shape to otherwise unwieldy clothes. Antoinette might also insist you carry yourself upright, walk gracefully and keep your head up, as all fashionable ladies should.
4. Get the right fit. As you lose weight, try to find pieces that fit you at the moment, not weeks from now. I say this because when you do lose that weight, you don't know how your body is going to shape up. Thus, you might buy this great dress, lose the weight to fit in it but it still doesn't mesh with your new body.