Add Leather. Make it Black.
Black leather, 1992: Biker jacket
Grunge had a way of making black leather look more careless than tough, even with the punk-remnant studs that sometimes spattered cuffs and collars. As Taylor Momsen can attest, this is about the easiest grunge element to incorporate into a modern look. The biker-style jacket, for one, may just be the most versatile piece of outwear you can own, even when it's not tossed over a stained, torn T-shirt. It simply doesn't go out of style. Wear this jacket. Done.
Or take it up a notch: Black leather pants are unmatchably tough-chic. The leather mini, too, makes a grunge staple sexy. But keep it to a single element (or maybe one large and one small), or else you're looking less glam-grunge and more biker chick than chic.
Black leather, revised: Black leather skinny pants; vintage-feel tee over pop-of-color layering tank
Moving, now, to the feet, and still on the black leather ...