The first and best way to ensure a healthy lawn is to cut it high. When you mow, you prevent seeds from generating and so your lawn, in turn, produces more sprouts frantically trying to find a way to regenerate. Just like with trees, the height of the top relates to the depth of it's roots. Grass with deep roots has a better chance to survive a drought and it also keeps the soil shady, preventing moisture loss and drying of the sun, which in turn, compacts the soil. A taller grass blade absorbs more light, has more nutrient producing cells, and it resistant to invading weeds.
The clippings you produce from mulching provide 50% of your lawns nutrient supplements. As it decomposes it produces nitrogen. Also, a thin layer of thatch holds in moisture and provides safe harbor for those ecologically friendly or beneficial insects (ground beetles, rove beetles, ants, worms).
Inspect your lawn prior to mowing. It is easier to spot weeds before you cut. Remove weeds upon discovery. Doing this when they are young is much easier than when they've had the chance to establish deep trafficking root systems.
4. Monitor water or precipitation levels:
Your lawn needs at least an inch of water a week. Put a container somewhere inconspicuous and watch how much water is collected during a rain or sprinkle. You may need to water if you haven't had rain. Place the can near a sprinkler to measure. And it's CRITICAL that you water between 6 to 10 am. Any later you will be losing moisture to evaporation as the sun gets warmer. Also, water will not saturate deep enough causing roots to stay near the surface instead of traveling deeper and gaining root strength along the way. Keep track off the length of time taken to fill the can, and then you can simply time your watering sessions.
A good spring fertilizer of organic material is best for your lawn. You can get great results with manure/humus mixtures and from using kelp, or seaweed. It is available in liquid concentrate and can be added to your sprayer applicator. Organics are better for your soil and in most cases much cheaper. And, in the long run you'll develop a more nutritious soil. Autumn fertilizing is the most critical of the seasonal applications to prepare for a long, cold winter.
Aeration gives your soil relief from impacting. Soil gets hard and tough for grass roots to develop, so by plugging holes all over your lawn gives the soil some relief. Oxygen is then readily available directly to the roots, water is more easily absorb. It is best done in either early spring, like March, or in June or September.
Removing deciduous leave and debris from your lawn prevents safe harbor for insect larvae to develop. And it also prevents an unbalanced Ph level.
Filling in your lawns bare or thin spots or high traffic areas can protect it from disease, insects and dry compacting.
If you've used chemicals for any number of years, you may have developed volatile soil. Grass becomes lazy and doesn't work as hard at photosynthesis. Beneficial insects cannot establish themselves and help your cause because the soil is too toxic. Start using organic fertilizers and bag your grass clipping for at least two months.
Good soil composition can do much more for achieving a low-maintenance lawn than anything you can do for your grass itself. This could arguably be number one because once your established good soil the rest is low-maintenance.