God is manifested in two forms - Nirguna and Saguna. The easiest form to realize God. The highest way of worshiping God in that easiest form

Lalitha

 (from "Quintessence of Sai Satcharitra" by Bodhi (Shuddhananda Brahmachari)):

Brahm (God) is manifest in two forms - Nirguna and Saguna. Guna means qualities, Nir means without, and Sa means with. Nirguna Brahma is where God is seen as a non-dual, formless, non-conceptual, non-definable reality with no definable qualities. Here, God can neither be seen in any form, nor can any particular qualities, be they divine or evil, or ruthless or compassionate, be ascribed to him. Nirguna Brahma is the totality of the infinite qualities and forms pervading the Universe and beyond all universes. Saguna Brahma is the God with particular divine qualities ascribed to him. He has ascribed a finite form and personified with a name and finite attributes. 

Although both are ways to perceive the same Oneness, still people are attracted to establishing their beliefs in either Saguna or Nirguna manifestations of God according to their spiritual state or their own innate mental setup brought along from previous births. Worshipping the Saguna God is the easiest and the best way to realize the Nirguna God. This is because the man himself is Saguna, which is a man bound by the limitations of a form, a name, sense preceptors, and specific individualistic attributes. This, it is much easier for him to conceive and emotionally relate to the God who has a form.

It seems much simpler to surrender our intrinsic qualities and emotions to a manifestation of God that we can relate to. We can naturally accept and understand God with finite human qualities such as love, compassion, beauty, grace, divinity, forgiveness, and so on. Unless one indulges in the worship of the Saguna God for a certain period, the tender qualities of the heart center such as love and devotion do not awaken in the seeker. But always remember that no matter whether one believes in the form or formless, if one worships with a pure heart, it reaches the same God for God is many, as much as he is one. The more we progress in the path of worshipping the Saguna God, the more we evolve, and our eyes are opened to be able to fathom the Nirguna, or formless reality. Thus, it is important to begin one's spiritual practice by worshipping the God with finite form.

The ways to worship finite manifestations of God or Saguna Brahm are many, such as - being deeply reverential to divine idols, altar, light, fire, sun, water, trees, saints, seers, pilgrimages, scriptures, places of worship, and so on. However, the worship of one's Guru is the highest form of worshipping Saguna God.