This is actually much trickier than it sounds. First of all, you’re better off using a polearm weapon like a pike, bo staff, pitchfork, or scaffold pole, as they don't lose so much height during a throw. You can attempt this whenever you come across zombies feeding on a corpse or hammering on a wall or gate, as they’re not staggering around and are easier to hit.

Throwing a weapon across Colt Swanson or Curtis Sinclair’s driveway in Bel-Air is one good place to get this, or, failing that, the open streets in Ocean Avenue, outside the Serling Hotel. Or the beaches of Santa Monica. Ready your aim carefully, and don’t aim too high, using the reticule to gauge the distance of your throw. Your weapon only needs to hit an enemy, so don’t worry about killing them. If your shots miss, keep using weapons until one hits - you can always recover them later.