Minecraft wiki entry for Door-based_iron_golem_farming, associated text: There are several approaches to building an iron farm, but efficient farms tend to use two floors in the golem-spawning zone (16 blocks×6 blocks×16 blocks) and keep all doors and villagers outside the zone, either above and below the center or in an outer "ring" on the same level. This is in order to maximize the number of available spaces for the golems to spawn in, which in turn will reduce the number of failed attempts, and keep the spawning rate as high as possible. This is much more effective than simply increasing the villager count to raise the golem cap, which only matters for the few seconds between the time when a golem spawns and when it is flushed out and killed. To further increase your output rate, you can build several separate iron farms as long as they are more than 64 blocks apart, and bring the golems or their drops to a central collection area. The most powerful iron farms are ones that overlap many villages. Since golems are immune to falling or drowning damage, the available killing methods are lava, magma blocks, suffocation, or a combination of these. As a more convoluted option, you can position a group of evokers to attack the golems in a holding chamber.