Not knowing your growing zone, I don't have much advice, but here is one thing that can help,
if you live in zones 4-8. This spring, just before the last frost date for your zone, lightly scatter some Dutch white clover seed through the lawn. The ground will heave slightly when it frosts, and that will get the seed down to the soil.
Clover fixes nitrogen in the soil, which the grass then feeds on. That way your lawn fertilizes your lawn!
Here is a picture of Dutch white clover roots. See all the little nodules? That is the nitrogen that your grass will feed on. It has the added benefit that the taproots help to aerate the soil, and it is fairly drought resistant. So even if you go a little too long without rain, your grass will look greener longer without having to water.
Plus, IMO, the little white flowers are pretty, scattered here and there throughout the yard. And it helps to feed the bees! Benefits all the way around.
Edited to add: It
is considered a weed. If you are going to use a weed killer on the grass, don't waste your money on the clover.