The secret is to NOT go totally ‘vintage’ from head to toe. There must be a mix of contemporary wear with vintage inspired apparel and/or accessories.
For example, you can wear a cropped jacket with skinny jeans and stilettos. You can also wear a "tango dress" (that's like a flapper dress) with a pointed-toe kitten heel shoes, or a pill-box hat and a modern tailored suit with a 3/4 arm length jacket.
Research and Study for Vintage Fashion Inspirations
If you need inspiration you can simply study the typical pieces of interest - skirts, tops, jackets, hats, coats, etc.., by reading old fashion magazines, purchasing cheap vintage fashion books on-line, or watching old classic movies and soaps such as I Love Lucy, or Happy Days.
Images, photos, and drawing illustrations will help you have a better understanding, not only of women's fashion apparel, but also vintage accessories, its art, and the history behind the pieces.
And if there is a particular style you desire, you can always opt for vintage dressmaking patterns and have it custom made by a dressmaker, if you can’t sew it yourself.
If you prefer to stick to modern trendy clothes, you can mix your ensemble with vintage inspired accessories. Collect old family pieces or buy vintage look-alike costume jewelry, but only appealing pieces that takes ones breath away like the typical 40’s and 50’s vintage jewellery designs.
It not going to be easy to find what you desire at your local high street boutiques or shopping centres and your best bet may be to find what you'll like on-line at vintage fashion stores.