To get a 1950's "New Look" outfit to fit correctly, the best way is to wear foundation garments. Our mothers and grandmothers wore foundation garments, such as girdles and waist cinchers or corsets on a daily basis. Most of us, including myself, were not born with a Maryln Monroe, physique. This is why a great many of the vintage dresses of the 1950's and 1960's have such a small waist in comparison to the bust. Because, manufacturers were aware that women wore foundation garments on a regular basis. [ On go into more depth on vintage sizing in another article. Check out the blog article on vintage sizing. ]
This girdle fits higher on the waist. With the lycra and elastic on the sides it pulls the waist in and keeps the hips smooth at the same time. Therefore, this type of girdle served as both a waist cincher and girdle. The clips are for nylons. At the time, nylons had clips and were attached to your girdle.
Then when the late 60's and 1970's came around, the A line mini and tent dress came into vogue. The fashion world switched from the hourglass form of Maryln to the straight thin boy form of Twiggy.
Today, we are lucky that we live in an time that we can dress as we like. We can dress in any era we prefer or just dress in a pair of cut offs and a T shirt. However, something I know from my husband. He still prefers to see me in a dress.