Hippolytus, a Roman clergyman, composed a manual of church order and worship known as the Apostolic Tradition around AD 200.  Hippolytus describes a Eucharist in two settings: one after the consecration of a bishop, and one after baptism and confirmation. We see the slow progression of church tradition very early in the second century. By the third century, the description takes on a clear formal liturgical style of a worship service.
At the consecration of a bishop, the Eucharist begins with the greeting or kiss of peace. Deacons then bring the elements to the bishop, who with other presbyters (elders) lays his hands on them. Introductory responses, still used in many liturgies, are then spoken:
The Lord be with you.
And with your spirit.
Lift up your hearts.
We have them with the Lord.
Let us give thanks unto the Lord.
It is fitting and right.
The eucharistic prayer is longer than in the previous examples. It starts with thanksgiving for the coming of Jesus and Christ’s sufferings through which he abolished death, to the words of Jesus’ institution of the Lord’s Supper and the anamnesis (recollection) of Christ’s death and resurrection. The prayer concludes with the invocation of the Holy Spirit upon the assembly and a doxology.
He explains that if the oil is offered as a gift, it is then blessed, symbolic of the anointing of kings, priests, and prophets. A doxology concludes the ceremony. If cheese and olives are offered, they are similarly blessed as symbolic of charity and of the free flow from the tree of life, with a concluding doxology.
In Hippolytus’ second example, the Eucharist after baptism and confirmation, the ceremony begins with the offering by the deacons of bread, wine, milk, honey, and water. During the prayer that follows, which Hippolytus does not quote, the bread is to be eucharistized into the “flesh of Christ” and the cup of wine into his blood. The mixed milk and honey, symbolic of the promised land and the nourishment of Christ, is blessed, and also the water, symbolic of cleansing. The bread, and cups of water, milk, and wine are then distributed by the presbyters. The cups are served to each worshiper three times, with the following dialogue:
In God the Father Almighty. Amen.
And in the Lord Jesus Christ. Amen.
And in the Holy Spirit in the Holy Church. Amen.
In the Apostolic Tradition of Hippolytus, we note that the elements of the Eucharist are viewed as the representation of the flesh and blood of Christ, having taken on this property through the eucharistic prayer. There is now an invocation of the Holy Spirit (epiklesis), but it is upon the people rather than upon the elements of the Eucharist as in later practice. The church hierarchy shows a greater differentiation; the president is now a consecrated bishop, elevated above other presbyters. There is a more elaborate use of symbolism suitable to the different occasions on which the Eucharist is celebrated, but the service of the Word is not mentioned in these examples.
Already by the second century, Christian worship had developed beyond what is described in the New Testament. There is a tendency to invent new symbolism not directly present in Scripture.  In some cases, it is hard to establish a clear link between early Christian liturgies and the practice of saints in the New Testament church.
One thing is clear, though the approach and methods are different, second-century sources show that Christians of that time centered their worship service around the Lord’s Supper or Eucharist, accompanied by the proclamation of the Word of God.
Also, the church was moving from Jewish culture into Graeco-Roman culture and was undergoing a transition. The emphasis was shifting from being the people of God to explaining issues of Christian theology. This begins to appear in the writings of the early “fathers” of the church and in early doctrinal debates and is reflected in the development of the liturgy. There is a growing tendency to define the way in which the bread and wine are identified with the body and blood of Christ.