Upaasanaa is a combined word - Up means near, and Aasan means sit; thus Upaasanaa means to sit near Bhagavaan with Bhakti to offer his devotion. Worship. It makes the person see the object of his search and bringing into closer contact with it.

In Padm Puraan, 5/35, Mahaadev Jee said to Paarvate Jee - "There are several kinds of Vishnu's Upaasanaa (worship) - offering water, doing Jap of His Mantra, meditation on His forms, remembering His names, Keertan (chanting His names), listening to His stories, worshipping, taking His Charanodak, taking His Prasaad, serving His Bhakt, observing Dwaadashee Vrat, planting Tulasee - these all ways are of His Bhakti...."

Upaasanaa consists of two parts - Dhyaan (meditation) and Jap (recitation).
One should keep four things in mind regarding Jap - Shraddhaa, Vishwaas (faith), continuity, and regularity.

Upaasak
Upaasak or worshippers are of five types - devotees of five principal sects : Shaiv (Shiv), Shaakt (Devee), Ganapatya (Ganesh) , Saur (Soorya) and Vaishnava (Vishnu).

The sixteen syllable Mahaa Mantra,
"Hare Raam Hare Raam, Raam Raam Hare Hare |
Hare Krishn Hare Krishn Krishn Krishn Hare Hare ||/p>

has two ‘akshar’ (letters or syllables) each. And for the sixteen nodes we hence have thirty-two Gun (characteristics).

He who does the Haran of ‘Sansaar’ (worldly existence) is Hari Naaraayan.
He who does he Haran of ‘A-Gyaan’ (ignorance) is Shiv.
He who does the Haran of ‘Dur-Gati’ (misfortune) is Durgaa.
He who does the Haran of ‘Vighn’ (obstacle) is Ganesh.
He who does the Haran of ‘Andhakaar’ (darkness) is Soorya.
Thus the term Hare applies to all five types of Upaasak.

The word Raam is ‘Par Brahm’. The word Raam came into existence even before the incarnation of Raam. When King Dasharath and Kaushalyaa were blessed with Raam, he approached Sage Vashishth for naming ceremony. The word Raam is to bestow one with ‘Sukh’ (happiness) to all the three worlds. By uttering the word Raam, the mind is removed from all the stress and is filled with calmness. While the word Krishn means something that attracts our mind. Thus, even if one chants the Mahaa Mantra with a worldly desire in mind, the power of Mahaa Mantra is that the Lord not only satiates that person’s worldly desire but also bestows Mukti. Such is the greatness of this Mahaa Mantra.

Sa-Gun Upaasanaa
Upaasanaa is of two types - Nir-gun and Sa-Gun. In Nir-gun Upaasanaa, one worships Brahm without attributes - without shape, form, color etc; while in Sa-Gun Upaasanaa one worships Brahm with a definite Swaroop (form) like Raam, Krishn, Narasinh etc. Sa-gun Upaasanaa is commonly understood as idol worship or Moorti Upaasanaa. Every object in the world, animate or inanimate is a manifestation of the one God. If one realizes this truth one will do no evil. One should begin by seeing God at least in one object through concentration upon that particular object as God - which is true by itself. The grace of God resulting from such intense concentration will enable him to go further and see God manifest in all that is and thereupon he will be free from the limitations arising from non-experiencing the truth that God is in all things.

It is a misnomer to regard Moorti Upaasanaa as an idol worship. The true worshipperof a Moorti never feels that he is worshipping a stone or a piece of metal. He thinks only of God in it - forgetting all else! When Arjun was steadying as directed by his Guru to take correct aim at a target, his master Drone asked him what he was looking at. Arjun answered, "I see only the eye of the bird!". Other disciples lacked the concentration that Arjun had. This is an illustration of the true true devotee's mental state at the time of worship of his chosen Moorti or deity. He sees only god in the Moorti of his worship, not the material of which it is made. From this stage the aspiring devotee can progress to the stage when he sees God and god only in everything around even in the small atom. This stage is the culmination of the spiritual effort of which Moorti Upaasanaa is a beginning.