If you want to seed a new lawn these are the steps you should take to achieve a nice lawn:
Choose your seed—You need to consider the environment of your lawn when considering what seed to use. Is the lawn shady or does it get full sun all day? Does it get a lot of traffic? Scotts has several premium seed mixtures to choose from. Use the advice found on this site to choose the right grass for your lawn.
Prepare the seedbed—Prepare the seedbed by having the area plowed and disced, or by using a rototiller to till the top few inches of soil. If leveling is needed, it can usually be done with nothing more than a shovel, wheelbarrow and a garden rake.
Adding topsoil is unnecessary, unless you need it for filling low areas. TIP: Don’t work the soil too finely, as this makes the surface crust over and dry out too quickly. Soil particles from pea-to-marble size are ideal.
Sow the seed evenly—Use a drop or broadcast spreader. Spreading by hand is not recommended, since obtaining uniform coverage is difficult.
Be sure to fertilize—Applying starter fertilizer will help new seedlings develop faster and grow into a thicker, greener lawn. After applying seed and starter fertilizer, rake the area lightly to work the seed about 1/4 inch into the soil.
Mulch—Mulching is recommended to reduce the frequency of watering on flat areas.
Water is crucial—Watering is crucial to seedling success. Only the top inch of soil needs to be kept moist, so watering frequently rather than deeply is best.
Mowing and fertilizing—When it’s time to mow, set your mower at a height of about 1 1/2 inches. Be careful not to damage the young plants. Remove clippings so seedlings will not be smothered.
Many weeds will be eliminated by regular mowing. Others can be treated by applying one combination weed and feeds, after the lawn has been mowed at least four times.