"And they continued steadfastly in the apostles’ doctrine and fellowship, in the breaking of bread, and in the prayers. (Acts 2:42)"
"...pray without ceasing,..." (1 Thessalonians 5:17)
The prayer life of an Orthodox Christian consists of two important and ultimately inseparable parts: private prayer and liturgical prayer. To say that we only really need private prayer and that going to church is optional is to deny the fact that Jesus founded a community, not a philosophical movement or even a religion. To say that all we need to do is go to church for an hour or two each week is to deny that Jesus taught us to pray privately (Matthew 6:6). Both are important, both are essential, but neither is sufficient.
The corporate worship of the Orthodox Church consists primarily of the following:
(1) The Divine Liturgy, originally written in the late 4th or early 5th century, is the main Eucharistic celebration of the Church. It consists of two main parts which historically grew from the Jewish synagogue and temple services. The first part focuses on the Scriptures, with the high point being a reading from one of the Epistles and a reading from one of the Gospels. The second focuses on the Eucharist, which Orthodox believe to be the Body and Blood of Christ. Those familiar with the Roman Catholic Mass should be able to see in the Divine Liturgy the same basic structure. The people stand for the entire Liturgy (except possibly for the sermon), which takes approximately two hours and is chanted (a capella, including the reading).
(2) The daily cycle of prayer, which includes Vespers, Compline, the Midnight Office, Matins, and the Hours (1st, 3rd, 6th, and 9th). While all of these can be said privately, especially when the service is not offered at a local church, the intent of these services is for the community to come together to pray. For the most part, the only communities that hold all of the services on a daily basis are the monastic communities (monks and nuns).
(3) Other special services, such as weddings, funerals (called the parastasis or panikhida), and akathists (special canons of prayers for things like the beginning of the Church year).
To understand all of this from an Orthodox standpoint, you need to realize that the services are ancient. The structure of the services of the daily cycle dates to the first century, and is essentially a Christianized version of one of the sets of daily prayers mentioned in Acts. Specifically, in Acts 3:1 it mentions the prayers of the ninth hour, Acts 10:9 mentions the prayers of the sixth hour, and Acts 2:42 is properly translated “…in the breaking of the bread and in the prayers,” meaning the daily cycle of prayers. The daily cycle of worship was common in Judaism at the time, and is common in Orthodox monasteries to this day, where “day” refers to sundown to sundown, not midnight to midnight).
Incense is used throughout the worship services of the Old Testament, and is also mentioned in the book of Revelation when describing the worship of God in heaven. As such, incense is used extensively in Orthodox worship. The deacon censes the iconostasis, the icons around the church, and the people, and the idea is from Psalm 140 (LXX): “Let my prayer arise to You as incense…” The incense represents the prayers from us and from the saints rising to God.
It should be obvious that we Orthodox do not see a need to invent or modernize our services; we see our services as being the Christian worship handed down to us by Christ through the Apostles, and as such there is no need to change anything. The common word we use to describe this is Tradition (with a capital "T", indicating that we believe this to be the Tradition of God and not the tradition of men). Admittedly, the danger exists that saying essentially the same prayers every day and every week can become more rote and ritual than actual prayer. However, a closer examination reveals that the danger of prayer becoming something is isn't supposed to be exists in every tradition. If the common parts of Orthodox services become mere repetition, they lose their meaning. If, on the other hand, there is a realization that these prayers are repeated because they are the most important prayers, then paying extra attention to them and praying them all the more fervently becomes the norm…as it should be. The same thing can happen with the Lord’s Prayer…try praying it slowly, line-by-line, and you’ll see what I mean. “Spontaneous prayer” can quickly devolve into a long string of “please God do this for me” type prayers, at the expense of both praise and worship. And none of the above, even if taken seriously, can really get us close to 1 Thessalonians 5:17, “…pray without ceasing..."
Sadly, private prayer can also devolve into the above mentioned "prayers". To this, Orthodoxy offers one a deceptively simple prayer, basically an extension of the “Lord, have mercy” from the daily services, known as the Jesus prayer: “Lord, Jesus Christ, Son of God, have mercy on me, the sinner.” Lots of books have been written on this prayer. It is full of the essential doctrines of Christianity, and prayed slowly and seriously, it is a surprisingly powerful prayer. Again here, though, if it becomes just “vain repetition”, then it’s a waste of time. I say this prayer a lot every day, and allowing it to run through my mind even when I'm not trying to say it is as close to 1 Thessalonians 5:17 closer to reality as I have been able to get.
That's not to say that "standardized" prayer is everything or that "spontaneous" prayer is all bad. Both can be positive, and both can be misused and misdirected. Ultimately, what we need to keep in mind in prayer is what we need to keep in mind in everything: Thy Will be done. Worship should be done according to God's design, not according to our tastes. God knows our need better than we do, so there's really no need to ask for specifics, especially since we often don't know what we really need.
So when it comes to prayer, it should be no surprise that the way Jesus taught is to pray has, at its heart, the phrase that is easy to see but difficult to live: Thy Will be done.