An easy start:
Change door handles and hardware. They're probably not in good shape, and it's an inexpensive, simple way to add elegance and color.
Get rid of toilets that are not water-conscious and appliances that suck energy. When you buy new appliances, go with stainless steel. It's modern but has an old feel.
And what stays:
Light fixtures may just need to be shined or given a new lampshade. Hardwood floors are keepers — if they are orangey, switch to an ebony-colored stain. Keep claw-foot tubs and old sinks. If they are cracked, yellow and gross, a porcelain company can respray for about $150. They don't make doors like they used to either. Old doors are usually solid with nice molding.
Get out of the '90s:
People went overboard with faux and sponge painting. It dates a place. Some homes from that era also have an awful lot of brass. Paint it black, bronze or silver with spray-on Rustoleum, which is great for small projects. It adheres to and protects the surface and it prevents rust.
Where to shop:
Restoration Hardware has new doorknobs and all kinds of hooks and fixtures that look vintage. For old hardware in great condition, go to Liz's Antiques on La Brea. Details on La Cienega has everything from door handles to mailboxes.