First mow efficiently and responsibly. If you don't use an area for the lawn consider allowing it to become wildflower areas or plant a garden there, or just mow it a little less often. You don't have to mow every part of your yard every week.
When you mow the lawn cut the grass on the high side. Mowing high has several advantages that start with the roots. Taller grass grows deeper roots. Deeper roots are better able to find water beneath the soil which means a better tolerance to drought. Taller grass also reduces the light that reaches the soil surface that weed seeds need to germinate giving you a less weedy lawn without chemical herbicides. Never scalp your lawn! If you cut the lawn too short you will allow those weed seeds to germinate and your grass will eventually die.
Tolerate weeds! Yes I said tolerate them. The "ideal" lawn with no weeds and a perfectly maintained grass like in the movies is hard to come by without dosing your landscape in chemicals that do more harm than good but you can get a pretty good lawn using all organic techniques. Clover is one plant that always gets a bad rap when in the lawn. It is really a beneficial legume that adds nitrogen to the soil. Clover is also a great flower for pollinators. Where do you think clover honey comes from? If dandelions pop up and you don't want them go harvest the flowers or mow them before they go to seed. That will reduce the amount of dandelions that germinate.
Fertilize with compost! You hear all the time when companies try to sell you their lawn care products about feeding the lawn. That's the wrong thing to do. Feed the soil. Healthy soil will make a healthy lawn or garden more sustainable. Get out a lawn spreader and put some finished compost in it then spread it over the lawn. The beneficial microbes in the compost will help the soil all over your yard. Compost will also go a long way toward improving soil compaction in the lawn. Most homes today are built on lots that have been stripped of topsoil. By adding compost you help to build that layer of topsoil back. You'll want to do this several times per year to see the greatest benefit - the more the better.
Know your lawn's type of grass. Cool season grasses like fescue enjoy cooler weather. In the summer they go dormant then come back later and there is little use in watering them through the summer. Bermuda and other warm season grasses are dormant in the winter but are green through the hot summer months.
Plant an annual grass like rye in the fall to help fertilize the lawn. An annual rye grass will eventually die off when the summer heat hits and will add organic matter to the soil. It also improves aeration as the roots decay which makes a better soil environment for the perennial grasses.
Overseed perennial grasses in the fall. I try to change the type of seed I overseed with each year so that my lawn becomes a mixture of several different types of grasses. This prevents it from being a total monoculture. When a grass doesn't do well others will pick up the slack!
Will you have a perfect lawn with these techniques? It depends on your perspective. Is a healthy, chemical free, pollinator friendly, and diverse landscape perfect? It sounds good to me!