IC XC NIKA
You should expect a bunch of crazy Egyptians.
Okay, as a norm, when entering the church, remove your shoes, and go to your right hand side (since gererally speaking, that is where the females sit). It isn't a doctrine, of course, but you might feel weird being with all the males on the left side of the church. Hmm, also as a norm, not a doctine, you should have a head covering (haha, not a baseball cap, of course). In my church, they have some at the front of the church, but if you don't feel comfortable wearing one, you are free not too.
Unlike EO and most Eastern Rite Catholics, we make the sign of the cross from the left shoulder to the right, like Latin Rite Catholics.
Hmm, also, don't be nervous. You will obviously not know what is going on your first time, espically if the liturgy uses a lot of Coptic and Arabic. Don't worry, haha, just keep at it, you'll get it eventually. There is going to be a lot of incense, sooo, well, you'll feel clean inside (trust me, the priests in the Coptic Church love the incense), breathing in all that incense. When you aproach Abouna (that is, the priest) after the Litrugy, he will rip a piece of the left over bread that wasn't used in the Litrugy (it is called Korban). Just peck his hand or hand cross (with you lips), and take the bread from his hand.
You also won't have to worry about fasting for the next 50 days, okay, till pentecost. However, I must tell you, our bishops are obsessed with fasting. So, talk with Abouna, he'll instruct you on the fasting rules. As I said, we fast a lot, so I hope you like soy products, because that, with nuts and peanutbutter are going to be your only source of protein for the big fasts.
I don't know what else really too say. The people at my church are very kind. OHHHHHHH, okay, one final note. You have to remember you are going to a Egytian church. Cover up fairly well. I'm not saying you have to dress like a nun, but where not to tight pants or dress, and a simple shirt. However, also remember, that sometimes Orthodox Churches can put their culture as Orthodoxy. Allow Abouna to help you distinguish; ohh, and all Abounas have BEARDS, so don't be afraid.