Vintage fashion sets you apart from the mass produced items of today. Every bit of fashion is a "knockoff" of previous fashion from another era.
This trend started for me in college. Since I was short on money, I mixed vintage items with modern fashions. I wore my grandmother's rhinestone pins on my sweaters. My Dad's 1960's wool sweaters were mixed with jeans and mini skirts, creating a "new look" for myself. Over sized sweaters (Mr. Rogers' style sweaters) over polo shirts in pastel colors with coordinating skirts and jeans was a staple . I had fun with this look because it was created by me and not a mimic of someone else
My favorite style eras are the 1930's and the 1940's which fits my rectangular, boxy physique. With the resurgence of these styles being reproduced in simplicity sewing patterns, it is now easier to reproduce those looks. You don't have to get an authentic dress from the particular era, you can reproduce the look, once you are familiar with the style you like and want to emulate.
By mixing, a modern outfit with vintage items, bingo! You have built your personal vintage style.