Give the lawn a good hair cut (except fescue) by making sure your mower blades are sharp. A sharp blade cuts evenly and does not tear the grass. Don't mow wet grass and the rule of thumb is to cut no more than one third of the grass height at any one time. If the lawn has been untended and it has grown tall, trim it down to its proper height in several different mowings.

Mowing height; mow

Kikuyu at 20-30mm

Couch 15-25mm

Buffalo 20-40mm

Mow at the maximum height prior to winter or in shady areas. Your new living carpet generally needs mowing 10 to 14 days after installation (in warm season).
The basic mowing rule is never remove more than one third of the leaf blade during a single mowing..
Mow when the turf cannot be lifted. Direction for the first couple of cuts should be in the same direction as the turf has been layed, this will help prevent scalping..
Set your mower at a cutting height suitable for each selective grass..
For best appearance be sure to keep your mower blades sharp..