1. reseed, reseed, reseed
2. compost, compost, compost
3. mow that lawn high and recycle the grass clippings right back onto the lawn
4. spray the lawn with compost tea, this activates the micro organisms that are alive it the soil so they can get to work
5. water properly (long and deep and in the am)
6. only create lawn where you will use it and enjoy it.
the last is probably the best advice and most important! if you don't use your lawn, why do you have it? convert some to wildflowers, some to vegetables, some to trees, shrubs and other plantings.
the book goes into a lot more detail but there are many free resources such as videos on the safe lawns website. now's the time to get that lawn ready for next year, if you love it use it, if not get rid of it!