Christian worship grew out of Jewish worship.
Jesus Christ was a religious Jew who attended the synagogue, and celebrated Jewish festivals, and his disciples were familiar with Jewish ritual and tradition.
The first obvious divergence from Judaism was making Sunday the holy day instead of Saturday. By doing this the day of Christian worship is the same as the day that Jesus rose from the dead.
Jesus's promise to stay with his followers, fulfilled in the sending of the Holy Spirit, illuminated the development of Christian worship from early times.
* God is present
So Christians regard worship as something that they don't only do for God, but that God, through Jesus's example and the presence of the Holy Spirit is also at work in.
* The Eucharist and the Word
Church services on a Sunday divide into two general types: Eucharistic services and services of the Word.
Both types of service will include hymns, readings and prayers.
The Eucharistic service will be focussed on the act of Holy Communion.
The service of the Word will not have this rite, but will include a much longer sermon, in which the preacher will speak at length to expound a biblical text, and bring out its relevance to those present.
Different churches, even within the same denomination, will use very different styles of worship. Some will be elaborate, with a choir singing difficult music, others will hand the music over to the congregation, who sing simpler hymns or worship songs.
Some churches leave much of the action to the minister, while others encourage great congregational participation.
(Of course all churches encourage the full participation of the congregation in praising God with heart, mind, and soul, but some churches give the congregation more physical participation.)