Every family have their own tradition to celebrate festival and it changes from household to household, region they live. Here is an overview to celebrate the festival: Firstly, make a shopping list of what we need for the festival. Decorations, flowers, groceries, fruits, Ganesh idol, etc. Secondly, take head bath, clean the house - Pooja place, kitchen (sweep/ mop), decorate it. We draw maakolam at entrance and pooja place. Thirdly, place Ganesh idol and decorate it. Chant mantras (like 'Om Ganeshaya Namaha) or just wholeheartedly chant his name. prepare God's favorite food to offer. You can also offer his favorites like fruits, etc. Lastly, light lamp, arrange his favorites in front of him neatly. Offer it to Ganesha, do aarathi and pray for well being. Please read my other detailed post for more information (Link above)