Evangelism
Witnessing Orthodox Christianity is the process of bringing Orthodox teachings to people who are outside of the Church, in hopes that they will accept these teachings and decide to become a part of the Church. Witnessing can be done as an act of deliberate missionary work, or evolve from a casual discussion about faith between an Orthodox Christian and a person (or people) outside the Orthodox Church.
A witness for Orthodoxy can be either a cleric or a layperson. During discussions about the Orthodox faith, a prepared witness will know Orthodox doctrine and be versed in Orthodox apologetics in order to best answer questions. It can also be helpful if the witness is familiar with various non-Orthodox ideologies.
A witness for Orthodoxy can and should pray for God's help in his or her task.
Orthodoxy believes that only a person's free will can accept faith, it does not believe in compulsory or insincere conversions.
Prayers
For non believers: O Master, Lord our God, call to Thy holy Illumination Thy children who see Thee not and who believe Thee not, and grant them great grace to be renewed unto life everlasting.
Resources
Orthodox Witness, an online e-group devoted to the discussion of witnessing Orthodoxy