Sand the glazing off the shoes like 2speed said. As you do it, if it looks like there's oil or grease on the shoes, you need to clean them with Brake-Kleen. Spray, wipe off, and repeat until they're clean. Also use steel wool or sandpaper on the drum in the hub to remove any rust or corrosion. Grease only the pivot point and cam when you reassemble.
Unless you're rear cable is so stretched that the lever almost meets the hand grip, you don't need to replace it. Clean up the rear brakes the same way you do the front. Don't forget that there's an adjustment at the wheel as well as the lever.