Remove a circle of turf 10 to 18 feet in diameter, depending on the space available. Use a measuring tape to ensure that the center of the pitcher's mound is the proper distance from home plate. Distances vary from 46 feet in Little League to 60.5 feet in adult leagues.
Level the exposed soil with a garden rake. Pound a wooden stake or metal rebar post into the center of the pitcher's mound circle and mark the stake or post where it is 10 inches above the ground. Create a dense, heavy blend of sand, clay and silt, using two parts each of sand and clay for every part of silt. Pre-mixed blends of mound clay are available at some sports supply stores.
Spread a 1-inch-thick layer of the soil blend across the exposed ground and tamp it down firmly. Add a second 1-inch-thick layer of the soil blend on top of the first in a concentric circle that measures 3 to 6 inches smaller all the way around than the original layer. Pack this layer of soil down firmly and add six additional 1-inch-thick layers of soil, each 6 to 8 inches smaller in diameter than the layer before it so that the mound gently rounds as it rises.
Lay the pitching rubber on the flattened top of the pitcher's mound, situating the front edge of the rubber 18 inches behind the center of the mound. Add 2.5 inches of soil to the flat top of the mound, which should bring the edges of the mound flush with the edges of the pitcher's rubber while leaving a flat area across the top of the mound where the pitcher stands. Remove the stake marking the center of the mound and fill the hole with packed soil. Minimize erosion by covering the mound with a tarpaulin when rain threatens.