There are many types of grass, and all have slightly different preferences. No matter what kind of grass you plant, however, your first step must be preparing the soil. Readying soil for grass is less extensive than for other plants. Grass is not nearly as picky as flowers or vegetables about its soil, as long as sufficient nutrients are available and the area gets adequate sunlight for the type of grass you're planting. But if you take the time to prepare your soil well, your grass is likely to take root quickly and grow well into a beautiful lawn.
Test a soil sample. Either use a home soil-testing kit or call your local Extension Service office for places that test soil. The University of Illinois Extension states soil pH for grass should be between 6.00 and 7.00. If your soil falls above or below this, you may need to add lime to raise pH or sulfur to lower it to the soil to bring it within this range.
Remove sticks and other debris from the soil. Use a leaf rake to remove leaves and smaller sticks or twigs.
Till the soil with a rotary tiller, unless you have a lot of weeds. If the area is full of weeds, pull out as many as you can before tilling the ground to avoid spreading the weed seed. Till at least 3 inches and up to 6 inches below the surface. If you don't own a power tiller, you can use a manual tiller, shovel or even a garden spade--but tilling will be much easier and faster with a powered rotary tiller.
Break up large clumps of dirt with a shovel or spade. Rake the soil with a garden rake (a rake that has thicker, heavier tines that are farther apart than a leaf rake) to level it out.
Remove any newly discovered weeds by hand. Do not use a weed killer on the soil or your new grass will not live. Discard weeds in closed plastic bags so the weeds won't take root elsewhere. Fill in any holes in the area with top soil.