The important thing with the festival is the offering of food to the Mother Goddess, which is known by the name Pongala. However, pongala is not made at home.
Those who wish to do the pongala, go to the temple or to the surroundings of the temple very early in the morning. Some people even come the night before, if they can stay somewhere nearby. In the early morning of the festival day, everyone finds a place near the temple surroundings where they can prepare the pongala in the traditional way.
If you wish to go for the pongala festival, you may take the earthen clay pots to prepare the food. You also need to bring other necessities like the spatula, spoons and other utensils. And you have to find a place where you can make the food traditionally in the traditional ovens. You can probably find bricks to make the oven, but mostly you have to bring the woods needed to burn fire in the oven. Make sure you also bring all the ingredients you need to make the pongala - like rice, jaggery coconuts, and vayana leaves if needed.
Once you have find the right place and set the oven, you can fill the pots with water and rice, in order to prepare the pongala. However, the chief priest from the Attukal temple has to pass the divine fire which you can use and then pass on to others.
After the pongala is prepared, everyone wait till the holy water from the temple is sprinkled, after which the food can be served. By sprinkling the holy water, the belief is that you have offered the food to the Goddess.
You do not have to fast on the pongala day, provided you take only vegetarian food. Many people prefer not to take even water until the pongala is prepared. However, this is not a must.
Since the festival falls on either late February or early March every year, the weather is too hot during the day time and you may need to bring enough drinking water to help yourself stay hydrated. Actually you can find so many people offering drinking water to the devotees, but it is a good idea to have some water with you. If possible, find places where shades are available, like somewhere near trees, so you won't be tired. Those who have friends or relatives staying near to the temple, usually find a place near to their houses so that they can take rest in between.
The below image from Wikimedia Commons Image may not necessarily show the pongala made at Attukal temple, but the image shows a typical pongala offering made in the traditional way. Please note that the rangoli designs that you see here are not necessary for Attukal Pongala.