Let your grass grow long enough so that when you cut it there is still enough grass left to lie down. Wait until your lawn is at least 4 to 5 inches long so you can mow up to a third of the grass blades, leaving 3 inches of lawn.
Find the longest side of your yard, and use this as the straight edge for making your first cut. Cut the ends perpendicular to this edge before getting started so you have a place to turn around.
Make your first pass, keeping the mower as straight as possible. Turn around for your next pass, but overlap the previous cut by about 6 inches. As the wheels of the mower press the grass down and the twisting of the blades pushes the grass, you are left with stripes in the lawn.
Cut at a right angle to the first line if you want a cross-hatch pattern. Instead of turning and overlapping slightly, skip one mower’s width after each pass.