I find it is usually best to find a menu - either an old paper one that you have stuck in the drawer with the sandwich bags and coupons, or a lot of restaurants also put their menu's on line. Then, especially if others are with you that will be involved, you should probably discuss your order collectively -- will there be individual requirements? Or will there be sharing of resources?
After that, especially if you are unfamiliar with the order, or it will be a large order, it might be a good idea to jot yourself a few notes, just to make sure you don't forget something -- for example, I forgot the shrimp chips the other day; not a deal breaker, but I had a hankerin', you know?
Anyway, then make your call to place your order -- I recomment being in a quite room away from the group (no need for some smart-ass calling our things in the background to confuse the order-taker, especially if you are dealing with a foreigner still struggling with the language, such as you might find with a good Chinese establishment, and then make sure your order is verified if you are at all concerned. It's best to just give name and phone number and not pay over the phone...just too risky.
Alternately, a growing number of establishments have on-line ordering, which is very handy, especially if you will be ordering regularly and they can save "favorite" orders for when you return.
And...I think that about wraps it up. That covers the basics of ordering. I'm sure I missed a few nuances and tips and tricks.
Next time perhaps we'll talk about ordering in person, and discuss situational strategies, including: Ordering alone but want the waitress to think you are waiting for someone; ordering with your (especially elderly) parents, which includes slipping a "full tip" on the table after the parents have left some pittance "because the damn girl never brought me more coffee" (she left a pot on the table...sigh...); ordering on a first date when you are a cheap bastard but still want to impress your chick; and ordering in a foreign country when you don't speak the language.
OK then, thanks and we'll see you next time!