When inspecting the blade, make sure the mower is off and the spark plug has been disconnected. Then wedge a block of wood between the blade and the mower housing to keep the blade from spinning as you loosen the connecting nut. This is also a good time to grab a putty knife and clean the underside of the deck. Make It Even . Mow only when the grass is dry.
Wet grass is slippery and it leans, making for uneven heights and clippings that clump up.
Change the pattern each time you cut. This prevents the mower wheels from creating ruts. It also helps keep the grass growing upright. Level high spots by peeling back the grass and its roots and eliminating some dirt beneath. Keep grass away from the base of trees.