Sod is the easiest and speediest method to achieve a mature-looking lawn turf. Depending on your climate, sod can be laid year-round, including in late fall. The timing requirement would be that the sod be laid at least five weeks ahead of the first hard frost in your area. While sod looks mature when laid it is still in the delicate stage of establishing its roots in the new soil and should always be treated as if it were a tender young plant.
Till up the planting soil to a depth of at least 10 inches with a mechanical rototiller or a shovel and rake. The goal is to loosen the soil and remove any stones and hard clumps of clay. This will also give you the opportunity to inspect the condition of the soil and determine needed amendments.
Amend the soil with generous amounts of compost so that you are applying at least a 2-inch thick blanket all over the planting surface. More compost is better. If you have heavy clay soil, amend with sharp sand to improve drainage. Finally add a lawn starter fertilizer to give the roots a nutrient boost and counteract all of the watering that will be done, which washes nutrients out of the soil but is necessary. Till all the amendments into the first few inches of soil and rake to a smooth finish. Water the entire planting surface without displacing any of the level soil.
Roll the sod out, laying down the longest run length first against a straight edge. Stagger seams of the proceeding lengths, making sure to snug up the seams tightly but not so they are buckled or overlapping. Use a lawn roller or pat down the sod into the prepared soil to make good root-to-soil contact. Stand on the soil when laying each new piece of sod and gently rake the sod surface to remove any hand or foot prints and stand the blades up.
Water the sod in deeply until it is soaked. Use a spray attachment on your hose to create a gentle rainfall that does not move the seams or dig into the sod when sprayed. Keep the sod very moist but not sopping wet at its base for several weeks during the establishment period.