The orthoprax advaita tradition is closely allied to the smArta tradition, which follows the system of pancAyatana pUjA, where vishNu, Siva, Sakti, gaNapati and sUrya are worshipped as forms of saguNa brahman. In some sources, the concept of the pancAyatana is replaced by the notion of shaNmata, which adds skanda to the above set of five deities. The worship is done both on a daily basis and on specific festival occasions. Questions of who is superior, vishNu or Siva, which are very popular among many groups of Hindus, are not relished by advaitins. In the words of Sri Chandrasekhara Bharati (1892 - 1954), the accomplished jIvanmukta, "you cannot see the feet of the Lord, why do you waste your time debating about the nature of His face?"
That said, vishNu and Siva, the Great Gods of Hinduism, are both very important within the advaita tradition. The sannyAsIs of the advaita order always sign their correspondence with the words "iti nArAyaNasmaraNam ". In worship, advaitins do not insist on exclusive worship of one devatA alone. As brahman is essentially attribute-less (nirguNa), all attributes (guNas) equally belong to It, within empirical reality. The particular form that the devotee prefers to worship is called the ishTa-devatA. The ishTa-devatAs worshipped by advaitins include vishNu as kRshNa, the jagadguru, and as rAma, Siva as dakshiNAmUrti, the guru who teaches in silence, and as candramaulISvara, and the Mother Goddess as pArvatI, lakshmI and sarasvatI. Especially popular are the representations of vishNu as a sAlagrAma, Siva as a linga, and Sakti as the SrI-yantra. gaNapati is always worshipped at the beginning of any human endeavor, including the pUjA of other Gods. The daily sandhyAvandana ritual is addressed to sUrya. The sannyAsis of the advaita sampradAya recite both the vishNu sahasranAmam and the SatarudrIya portion of the yajurveda as part of their daily worship. In addition, "hybrid" forms of the Deities, such as hari-hara or Sankara-nArAyaNa and ardhanArISvara are also worshipped.
Full Article: Position of Bhakti in Advaita Vedanta Philosophy