Remember when getting ready for fall signaled a whole new wardrobe (grunge-rocker flannels and pleated jeans back in 1993, harem pants plus Tory Burch tunics for 2007)? Yeah, we really don’t, either. In recent years, street-style creativity and old-time thriftiness have dominated fashion. So now, a cool-weather update means taking classics from your closet — a little black dress, your fave skinny jeans, a simple white top — then amping them up with autumn trends: metallics, colorful leathers, printed pants. “It’s about mixing in what you’ve got — say a new peplum top with a classic pencil skirt,” says Julie Egermayer, owner of Adams Morgan boutique Violet (2439 18th St. NW; 202-621-9225). “If you buy just a few key pieces — a sequined jacket, a bright bag — you’ll update everything.” Shop this way, and you’ll look refreshed, not like a fashion victim circa 2012.