Step 1: Understand the need:
A lawn grows well only on a suitable site.
Two key points are sunlight and drainage.
Step 2: Factor 1 - Sunlight:
Most lawn grasses need an open site with direct sun for 5-6 hours a day.
A site under thick shade gives weak, patchy grass.
Step 3: Factor 2 - Drainage and soil:
The site should have good drainage and a gentle slope.
Waterlogging kills grass roots.
Fertile loamy soil gives a healthy turf.
Final Answer:
Two factors: plenty of sunlight (open site) and good drainage with a fertile, level soil.