Suklam baratharam vishnum sasivarnam sathurbujam
Prasanna vadanam dyayeth sarva vignoba santhaye.

All worship, puja or any rituals of Hinduism start with Ganesh puja  and He
is the first to be worshipped whenever we start anything.

Lord Vinayaka is the Son of Goddess Parvathi and God Shiva, the divine couple, Goddess Parvathi being the Shakthi, form forming half of God Siva's body while God Shiva being the Thrid God of Hindu God Trinity and the Destroyer of The Universe. Lord Ganesha, the elephant faced God, is the Queller of obstacles, Giver of Knowledge and Boons and the Remover of Darkness and Ignorance.

Lord Vinayaka has got an elephant face and human body. He is worshipped by
many names like Vinayaka, Ganesha, Pillayar, Vigneshwara, Gajanana,
Ganapathy, Mooshika Vahanaa, Modhaga priya etc. He rides on an animal called
mooshika(a large kind of rat).
SALUTATIONS to Lord Ganesha who is Brahman Himself, who is the Supreme Lord, who is the energy of Lord Shiva, who is the source of all bliss, and who is the bestower of all virtuous qualities and success in all undertakings.

MEANING: "O Lord Vinayaka! the remover of all obstacles, the son of Lord Shiva, with a form which is very short, with mouse as Thy vehicle, with sweet pudding in hand, with wide ears and long hanging trunk, I prostrate at Thy lotus-like Feet!"

Ganesha, the elephant-headed one, is one of the most popular deities of India. All auspicious events begin with an invocation to him. He is invoked before an act of business or trade, or before laying the first stone of a new building.

Images of Ganesha may be found in many different places - at the entrance to villages, drawn on the pavement in cities, or in wayside shrines on lonely roads. Reverence and devotion to Ganesha has spread from India, Tibet and Nepal, throughout south-east Asia and as far as Mexico.

Ganesha is usually portrayed as having the head of an elephant and the body of a huge-bellied man. In some depictions he is standing, whilst in others he may he dancing or sitting. As with the iconography of other Indian deities, the number of heads or arms an image of Ganesha possesses may vary. Ganesha is often shown wearing a serpent for a girdle and riding a mouse.

The pantheistic tradition of Hinduism accords primacy to the concept and worship of Ganesha. A common factor found in all schools of Bhakti-marga: Saiva, Saakta, Vaishnava, Ganapatya, Kowmara and Sowra - is the worship of Ganesha. Even the non-Vedic Veerasaiva cult admits His worship. Ganesha is worshipped with awe, respect, reverence and even affection. Devotees invoke his blessings at the commencement of any auspicious event, as he is the remover of all obstacles.