Sikhism is based on compassion; service; equality between males, females and all religions and encourages an honest, truthful living with a rejection of idol worship, the caste system, ritualism and superstitions. In Sikhism, heaven and hell are states of mind represented by joy and sorrow, bliss and agony or light and darkness.
Sikhism is a distinct religion and shouldn't be viewed as linked to either Islam or Hinduism. Guru Nanak Dev Ji said "I am neither a Hindu nor a Muslim, I am a human being".
Guru Nanak Dev Ji spread a simple message of Ek Onkar, we are all one, created by the one Creator of all Creation. He said that there is one God and the name of God is Sat Nam (truth). To show it's importance, Ek Onkar is the first line at the head of all gurbani and forms the first line of the Mool Mantar which begins the Guru Granth Sahib Ji.
Guru Nanak Dev Ji's followers were the Sikhs (the seekers of truth) and came from different communities and castes. Guru Nanak Dev Ji taught the Sikhs to bow only before God and that in order to experience God within themselves they should:
Naam Japna:    To get up each day before sunrise, bathe to clean the body before meditating on God's name and reciting the Guru's hymns to clean the mind. And throughout the day, to continually remember God's name.
"By repeating God's Name I have made God's temple;
O saints and followers,
Sing God's praises day and night." (Guru Arjan Dev Ji)
Vand Chhakna:    To share with others and support the entire community.
"Love of worldy things, like a snake
Has entangled the whole world in it's coils
Whoever holds it lovingly, gets bitten by it." (Guru Amar Das Ji)
Kirt Kani:    TTo work and earn a honest living. To practice truthfulness and honesty in all dealings.
"Truth is the highest virtue,
higher still is truthful living" (Guru Nanak Dev Ji).
By following this path, a Sikh can achieve liberation by becoming gur-mukh (God centred) instead of being mun-mukh (self centred).
There have been 10 human Gurus in the Sikh religion, each making a distinguished contribution to the development of the religion. Whilst Sikhs hold the Gurus in high regard they are not worshipped; Sikhs only worship one God "Ek Onkar".