Spring is right around the corner so it is time to start thinking about what you want to do with your lawn this year.
If your lawn was thick last year you could consider fertilizing the existing lawn. A thick healthy lawn will crowd out weeds. It may be all that is needed to keep the lawn going strong is some fertilizer and pre emergent weed control. Cut the grass at 3" and water as needed to keep a thick green awn all summer. With a thick lawn you generally want to over seed in the fall.
If your lawn was thin and had a lot of weeds you have a more difficult decision to make. With the mild winter we have had it is likely the weed seeds that are in everyone's yard will be germinating early this year. A thin lawn is prone to weeds. You will have two choices to try and get the lawn going. First you could consider aerating the lawn and over seeding it to try and thicken up the lawn, then using a post emergent weed control. With this course you would want to over seed again in the Fall. Depending on how thin the lawn is this could take two or three years to get the lawn as thick as it should be. Watering the lawn would be essential to get the grass thriving.
With either a thick or thin lawn another option after aerating would be to top dress the lawn if the soil is compacted. This IS an expensive option it involves multiple steps to do right and is very labor intensive. Part of the process is to measure the yard and bring in enough compost/topsoil to apply a 1/4 inch layer on the ENTIRE yard. It has to be raked in then watered in for best results. For best results it should be done when the grass is growing well so early Spring or Fall. For Spring especially you have to watch the weather, you need a couple of days without rain in the forecast, it is nearly impossible to spread the material in the rain. Top dressing will also help fill in ruts and low areas. If we have a wet Spring this can be difficult to get into the schedule.