There is nothing wrong with wearing head-to-toe vintage straight out of another era if you like—there are those who do this, love it, and are exceptionally good at it. However, my suggestion for a woman just getting started at vintage or trying to find the best way to incorporate it into her wardrobe?
Mix it up
Mix eras, styles, colors, patterns, high and low fashion. This takes some thought, experimentation, taste and knowledge, all of which can be honed.
About what to mix in. Slow fashion trumps fast fashion for many reasons. I think as we age we get to the point where considering that fact is somewhere between good thinking and a moral imperative. Vintage and 2nd-hand clothing should be a major consideration, along with ethically- and sustainably-produced new items.
When you mix vintage things up, consider matching certain elements:
• Color across eras
• Patterns that relate to one another
• Era but in an unexpected way
• Textural combinations that work across decades
• Timeless elements
I have already suggested Pinterest as a free and fun platform for exploring style ideas. I have just started (old dog, new tricks!) using Polyvore to bring items together into collages. This is another interesting way to see how things juxtapose.
Here are a few decade mash ups of vintage items currently available online to illustrate my taste in mixing. Enjoy finding your own way with the concept!