I have hated the way my own yard looks. So I have been reading about how to get the grass to look better.
Here is an overview of the articles, but feel free to read them.
Aerate your lawn
You may want to water your lawn first to soften the ground.
Aerating allows oxygen to get to the roots.
After aerating apply sand to fill in the holes.
You can use a machine, aerator shoes, attachment to mower, push roller.
Remove Weeds
You can manually remove weed by pulling them up by the roots.
Use a weed removal tool, such as a hand-held weeder or garden hoe.
Use a herbicide
Fertilize
Fertilize lawn a couple of times in the beginning of spring
Make sure product has nitrogen, potassium and phosphorous.
Schedule time to fertilize around Memorial Day, 4th of July, and Labor Day
Seed your Lawn
Apply grass seed in early Spring and early Fall
Use warm-season grass in Spring and cool-season grass in the Fall
Water often to allow seeds to sprout.
Cut your grass
Cutting thickens the blade of the grass.
Leave grass longer in the summer, so it can endure periods of drought.
Alternate the cutting pattern each time you cut to prevent grass from compacting.
Watering
Your grass needs about 1 inch of water a week. So if it rains you can do less.
Best time to water is between 6 am and 9 am.