A hard winter can sometimes cause a lawn to come back thin and sparse in the spring. To give your grass a thicker, lusher look, the best thing to do now is to overseed. First, choose the best type of grass for your region: You'll want to select a cool-season variety, such as Kentucky bluegrass, if you live in the north; if you live in the southern states, go with a warm-season variety instead. Prep your lawn to receive new seed by mowing, then apply the seed using a spreader to ensure even coverage. Lightly water the new grass on a regular basis, and keep off the seeded areas as much as possible until the new growth is firmly established.