The answer to 'how to maintain grass' is to establish a regular mowing, watering, and fertilizing schedule. Mow your lawn at the recommended height for your grass type, typically 3-4 inches, and avoid cutting more than 1/3 of the blade height at a time. Water deeply and infrequently, about 1-2 inches per week, to encourage deep root growth. Apply a balanced lawn fertilizer 2-3 times per year, following the product instructions for your lawn size and grass type.
Proper maintenance will help keep your grass healthy and lush. Be sure to also dethatch, aerate, and overseed your lawn as needed to address any thinning or bare spots. If you notice persistent issues like weeds, disease, or pest infestations, it's best to consult a professional landscaper for diagnosis and treatment.