Diwali is known as the festival of lights. It falls exactly 20 days after Vijay Dashmi. We light lamps called diyas to illuminate the dark. It is known that Lord Ram came back to Ayodhya with Ma Sita and Lord Lakshman. It was dark and that's why people lit their ways with diyas. Hence this day is day is known as Deepawali.
This day we worship Ma Lakshmi for wealth, Lord Ganesh for intellect and Ma Saraswati for knowledge. Children get new clothes and gifts. Everyone is happy on Diwali.
But we should be careful on this day as thieves roam the streets.
On Diwali our homes should be spotless, bright, there should be no trash and on Dhanteras, which lands 2 days before Diwali we should buy something precious like gold, silver, etc that we can afford. Only then will Lakshmi enter our house.