What? Find a seat? In Constantinople? IS OUTRAGE!
Yes, Is
Outrage! (Looks at pews in parish installed by otherwise very vostichnik pastor…)
Mark:
Wear comfortable shoes. Nice clothes, with layers.
When you enter, if at a byzantine rite (of whichever nationality), go reverence the icons: the one on the table in the middle of the aisle/nave (the tetrapod), then the icons of Jesus and Mary. Then find a spot.
Candle intentions: If there are big candleholders near the icons, with sand in them, find where the candles for sale are, and place a candle for each intention you pray for (or as many as you will afford) there, lighting them from the central candle, then putting the bottom of the candle into the sand to be held there during liturgy. There might also be roman style votive racks somewhere in the nave.
Crossing yourself: At entry and exit to the nave (and if allowed, the altar), at every mention of the trinity, during the trisagion (Holy God), when blessed, when incensed, and with every lord have mercy is when my parish does so. And when returning to one’s seat after communion.
If subject to allergies, have your antihistamines and/or inhalers with… some people react badly to the incense. More react badly to the often copious flowers present.
Stand when everyone else does. Stay out of the way of the processions - they go from the (as you’re looking on) Left door, around the outside to center back, and up the middle - and the incensation - out the left door, around the outside, up and back the middle, and in the right door.
Stay off the raised step up front - unless a cleric takes you there.
Confession, if going on when you get there, might be in a confessional, might be inside the altar, or might be in front of the Icon of Jesus on the screen or at a side table. If you see a priest with his stole over someone’s head, he’s hearing a confession - leave plenty of space.
If you arrive, with time to spare, and it seems like things have already started, enter, reverence the icons (waiting if a procession is in progress), and find a spot. It might be one of the other liturgical or paraliturgical prayers going. For example, if you arrive between 9:40 and 9:55 at St. Nicholas in Anchorage, you’ll arrive during 3rd Hour prayer… you’re not late for liturgy.
If you’re there early, don’t be surprised if it feels like everyone greets you - you will likely be noticed. Odds are good someone will hand you the needed books, and perhaps also suggest you stand/sit next to person ___, and if you get lost, you can ask them.
If there are chairs or pews, it’s best to be in them.
Certain ethnic parishes have traditional gender separation. If so, you’ll get the clue real quick - just move to the men’s side.