To have a healthy lawn it must be cut the right way, not just by adding chemicals and fertilizers. If you cut your lawn the proper way it will be green and healthy, and without crab grass or weeds. Maintaining your lawn cut the right way will be less work.
Your lawn should be three inches high after you have cut it. Not looking like a golf course. Having your lawn at three inches high will block weeds and crab grass, also it will absorb more sunlight, which makes it greener, and you happy. You basically only want to cut off the top third of your blade of grass.
Try to mow your lawn on a regular schedule, once a week is fine. This way it will not seem like such a big deal to mow the lawn. You still want to keep to the rule, of only taking off the top third of the blade.
You want the clippings to fall back in your lawn, the short clippings will compost the lawn and put the nutrients they contain directly right back into your soil.
If for some reason you get any small piles left behind, those you want to remove. It's those small piles you want to get off the lawn with raking.
Always mow your lawn dry. Mowing wet grass will only tear it. Torn grass ends up brown, and makes your lawn look like it is unkempt.
Cool temps is the best time to cut also. Cut late morning or early evening. You don't want to cut when there is dew on the lawn, this is the same rule as cutting it wet.
Change your mowing pattern every time you mow. This will avoid your lawn from having any paths, and you train your blades to grow in different directions. Different pattern mowing also makes your experience more fun.
Keep that blade sharp and clean to, get in the habit of shaping and cleaning often. This will make sure you have no uneven ends and will not have a brown lawn. Mow this way will also keep your lawn free from disease and fungus.