Remove large rocks and other debris from the garden area and wear protective gear, including boots, gloves and eye protection, when using a garden tiller. When the soil is damp but not overly wet, set the tiller to the desired depth. Make parallel, then perpendicular passes across the garden bed. Work amendments into the soil at a depth of 8 inches and till the soil to aerate the garden bed before planting.
Check the soil type to determine which setting to use when initially tilling the garden. Hard soil is tilled shallowly first, while softer soil is initially tilled at a deeper setting. Refer to the user's manual for the tiller to determine how to start the tiller and set the depth of the tines, as the specific instruction can vary based on the brand and model of the tiller.
After tilling amendments into the soil, allow the amendments up to several weeks to penetrate the soil, and till at a medium depth to aerate the garden.
After aerating the garden, till the garden perpendicularly a second time to prepare the soil for planting. Clean the tines of the tiller regularly when entangled matter is present, and before storing the tiller for the season. Turn the machine off before cleaning the tines.