If you want your lawn to look greener and fuller, then you need to start caring for it early on. Don't wait until it's already looking dry and patchy. In the early spring when the snow just only recently melted, you'll want to tackle these three essential lawn care tasks.
Apply an insecticide.
One of the main reasons lawns die back and begin looking brown is because they become infested with insects. From crickets to crane flies, these insects either feed on the grass in their adult stages, or their larvae work their way into the soil and eat the grass roots. Spring is the time to apply an insecticide so that it's present when the insects come out of hibernation and start laying their eggs again. Granular insecticides usually work best because they sit on the surface of the soil and slowly dissolve, leeching more insecticide into the ground over time. Look for one that is advertised to kill a broad array of insects, and sprinkle it on according to the instructions on the package.
Fertilize the lawn.
Fertilizing the lawn in the early spring before it really starts to green up is called "pre-emergent" fertilization. You'll want to look for a product that is marketed specifically as a pre-emergent fertilizer since it will contain the nutrients the grass needs at this particular stage. By fertilizing now, you help prevent the malnourished blades of grass from dying. If you were to wait until later in the season, you'd be trying to bring back already-dead grass.
Again, apply the pre-emergent fertilizer according to package instructions. Granular formulas are usually best since they don't require that you add any extra water to your lawn. (In the spring when the lawn is already wet, applying a liquid fertilizer could drown the grass roots.) Occasionally, you'll find products that combine fertilizer with insecticide. Feel free to use one of these in place of two singular products. Ask around at the shop, a place like Collins Lawn/Insect Control, for more ideas.
Rake up any lingering debris.
Hopefully you did a pretty thorough job of raking in the fall. However, there are always a few leaves or branches that blow into your yard over the winter. Raking these up is essential for lawn health. If there are leaves or branches on top of some blades of grass, those blades won't get enough sunlight and they will languish throughout the spring where they should be growing in strong.
By applying insecticide and fertilizer and picking up lawn debris, you can ensure your grass remains healthier throughout the upcoming year.