This is the best time to get at it!!! Prep work is required before you drop more money on fertilizer and seed. Make sure to rake any matted down areas and thatch buildup. If possible, aeration and de-thatching by a reputable company will do wonders.
Core aeration will help settle down lumps in your yard as well as open up the soil to be more accepting of water and nutrients.
De-Thatching will help expose the soil and grass roots for better penetration of water and nutrients. Too much thatch layer can choke out a healthy lawn making it look thin and sick.
Fertilizer is the key to developing a healthy lawn. Granular or liquid are both great choices. Speak with your local service provider to see what's the best choice for the stage your lawn is at.
If your lawn is thin and has bare areas, lawn seed is the best option to fill in the gaps. A custom blend that can be purchased from your local service provider is the best way to go.
Here's the magic wand. Make sure to water deeply and infrequently for best results. What does that mean? 30-45 minutes of water per zone if you have a sunny area with oscillating spray head.
Many people would like to have a lawn that looks like a golf green, but, can't dedicate hours every day to care for it. So, for a healthy weed free lawn it is best to keep it about 3" long and mow it at least once a week.
Weeds will choke out healthy grass. Manually or chemically remove weeds before they go to seed. Check with your local service provider to see what options there are.
After a year of enjoyment, mow low, and apply a fall fertilizer. This will prevent winter diseases from damaging your lawn and will also help it to come back greener sooner.