I visited an Orthodox Church once (not a service it was a festival and they gave a tour). Our guide was asked to explain some of the differences between Orthodox and Catholic and her fellow guide, who was a convert from Catholicism, explained it as best as he could. I've since looked up some more information and find it's biased from both sides.
One Catholic priest made references to the fact that Orthodox clergy can marry. It should be noted that so can Catholic clergy of certain rites. I've also read that the Orthodox use leavened bread for their service and Catholic don't. That's not true either. Again some of the Eastern Catholics use leavened bread. It's a bit unfair to use the Latin Rite as the litmus for what is Catholic belief versus Orthodox belief since many of the Eastern Catholics follow similar Orthodox traditions which are different than the Western Catholic traditions.
There is also this notion that Orthodox is more "mystical" since many of it's dogmas aren't as defined as Catholicism. I've read one Orthodox priest say that Catholics are too legalistic, which I find laughable since many of our own dogmas (the Immaculate Conception of Mary for example) aren't well defined either.
So I've compiled a list from several sources of what I know is true and factually different between all Catholics and most Orthodox.
The Holy Trinity
Christ as Savior
Christ's death and resurrection
Mary as Theotokos (Christ bearer) and Christ as God incarnate
Bible is inspired word of God
Holy Spirit guides the Church and faithful
Three fold ministry: deacons, priests, bishops
Importance of Apostolic Succession
Seven Sacraments or Seven Great Mysteries: Although they are given different names are essentially the same
Christ truly present in the Eucharist
Similarities in Church structure and art
Mary, being Theotokos, is supreme of all saints
Veneration of Saints
Use of religious icons
Use of incense, vestments, and ceremony as part of human worship experience
Belief in a Temporary and Final Judgement along with a Corporal Resurrection
Celebrate the Divine Office or Liturgy of the Hours
Similarities in Fasting and Almsgiving
Both do not recognize divorce but on occasion the need for married couples to separate (ie domestic violence cases)
Prayer for the dead
Jesus is both fully human and fully divine
Do not subscribe to Sola Scriptura
Do not subscribe to Sola Fide
Catholics- Bishop of Rome is supreme spiritual leader of Church. Orthodox- Patriarch of Constantinople is "First Among Equals" all 13 individual churches largely self-rule
Catholics have Filioque or the Holy Spirit proceeds from the Father and the Son. Orthodox says Holy Spirit only proceeds from Father.
Catholics believe that Mary was conceived without sin. Orthodox believe that Mary did not enter into a sinless state until she agreed to become the Theotokos at the Annunciation.
Catholics believe that we inherited Adam's sin during the Fall. Orthodox believe that Original Sin comes from the consequences of Adam's sin.
Orthodox church allows the laity more power in the decision to choose a priest.
Catholic bishops have a priest advisory board. Orthodox the Bishop rules together with a synod of priests.
Orthodox view salvation as trying to get closer to God (theosis) whereas Catholics view salvation as repudiation of sin.
Catholics have the doctrine of Papal Infallibility while Orthodox do not.
Catholics believe in Purgatory while Orthodox do not.
Catholics believe there is a limited number of Sacraments or Mysteries. Orthodox consider the Sacraments and along with sacramentals to all be Mysteries and therefore are not limited in number.
Catholics believe in confession of sins to a priest for forgiveness and penance and that the priest has the power to "bind or loose" sins. Orthodox believe that the priest acts as a spiritual adviser and help in overcoming sin to attain theosis.
Catholics reserve the Sacrament of the Sick to those who are critically ill, injured, or dying. Orthodox allow anyone in need-spiritually or physically to receive Unction.
Orthodox church encourages the restricted use of only two-dimensional icons whereas Catholics use statues.
Orthodox has more books in the Bible.
There's a bit more to it then this brief overview, but I hope this helps.