Determine how tall you want to mow your grass. Grass height must vary according to the season and type of grass. Don't cut your grass more than one-third of its height at one time.
Find out what brand of lawn mower you have. Depending on the type of mower, the wheels will adjust differently.
Locate the owner's manual for your mower type. Many websites for certain brands post their manuals online, in case you lost yours. You can also call for a new one, if necessary. Follow the instructions for your lawn mower make and model.
Place your lawn mower on a flat surface and locate each adjustment lever next to each wheel. The lever is located between each wheel and the mower.
Pull each lever at each tire in toward the mower and move the tooth or gear until the wheel is the height you prefer. Repeat this procedure for each tire until every tire is the same level.
Look for a lever on newer mower models towards the back of the chassis (the body of the mower) that will adjust the height of the chassis in one maneuver. The lever is usually near one of the back wheels and pulls out and away from the chassis.
Pull the lever out and then replace it in the appropriate groove.