Karva Chouth coincides with Sankashti Chaturthi a fasting day observed for Lord Ganesha. However on the day of Karva Chouth Lord Shiva and His family including Goddess Parvati, Lord Ganesha and Lord Kartikeya are worshipped. Goddess Parvati being Akhand Saubhagyavati is worshipped first during the Puja followed by Lord Shiva, Lord Kartikeya and Lord Ganesha. Women also worship Goddess Gaura and Chauth Mata who represent Goddess Parvati itself on the day of Karwa Chauth.

Sankalp
On the day of fasting, after taking morning bath women should take the pledge, which is called Sankalp, to keep the fast for the wellbeing of the husband and the family. It is also recited during Sankalp that the fasting would be without any food or the water and the fast would be broken after sighting the moon. The Mantra to chant while taking the pledge –

मम सुखसौभाग्य पुत्रपौत्रादि सुस्थिर श्री प्राप्तये करक चतुर्थी व्रतमहं करिष्ये।

According to Vratraj, the best time to perform Karva Chouth Puja is during Sandhya time which starts after sunset. Hence please note down the city based Karva Chouth Puja Timings after setting the location for your city.

Karva Chouth Puja is focused to seek blessing of Goddess Parvati. Women either draw Goddess Gaura and Chouth Mata on the wall or use Chauth Mata image on the printed Karva Chouth Puja Calendar to worship Mata Parvati. Goddess Gaura and Chouth Mata are representations of Goddess Parvati.