Hmmm, it depends.

Where do you live?
What kind of grass do you have?
Are you willing to water once per week in the summer?

Can you post a picture of the lawn and maybe one showing the mounds. Preferably take the picture on a cloudy day or in the shade, but not at night.

In the mean time, you can start applying organic fertilizer like alfalfa pellets (rabbit chow) (20 pounds per 1,000 square feet) or Milorganite. If you want the best, plan to apply once a month. If you just do that twice, you'll probably have neighbors sitting up and taking notice at the improvement.

The organic fertilizer advice applies no matter what grass type you have. Need answers to the questions if you want more detail.

Here's a picture to motivate you.

{{gwi:81154}}.

Those are side by side Kentucky bluegrass lawns...with a few differences.