1) Cremate your dead. Zombies, Vampires, Skeletons, and countless other abominations are spawned from dead human carcasses. Cremating them is the simplest way for them to stay dead. However there are spawns of other undeads, such as wraiths, ghosts, phantoms and so forth that could not be so easily handled.
2) Take down the source. Be it the original vampire, or a warlock practicing death magic, taking it out means saving the entire city. It takes kill 1 save a million to another level.
3) Install U-V lights throughout the inhabited cities. As seen on the movie "I am legend", many zombie-vampire hybrids, and also other undead beings doesn't fear light itself, but instead are vulnerable to the U-V rays. Each U-V lamp post should have its own internal power source that recharges in one way or another, and should the main power lines are cut, it should still work. We could connect every block to an underground nuclear reactor that never runs out. Or we could use a solar panel to keep it charged.
4) Beware of the fallacies that might cost you your life.
- As we all know, undeads of the 21st century are not affected by crosses, or holy water (because obviously, god is not real). It has seen no effect on the coven of vampires in "underworld'".
-They don't need your invitation
5) Evacuate and abandon the city once it's out of control. If the zombies are killing people faster that the people are killing zombies, you know you're in trouble. You can run, but you can't hide. station military troops on the outskirts of the town to prevent any outflow, and get a nuke down there immediately.