1) Standing - this is the normal posture for all Orthodox prayer, whether it be in Church or not. However, as you'll find many North American Orthodox Churches will have pews in them - more or less as something picked up from the local Christian denominations (though many would argue it wasn't a "good thing" to pick up.) If you were to go to the "old world", you'd be very hard pressed to find an Orthodox Church with pews in it.
However, don't feel bad if you feel the need to sit, especially since this is all new for you. It can take awhile getting used to standing for an entire service. It'll come on it's own.
2) "Prayer by rote" - Obviously, "ad libbed" prayer of a conversational sort has it's place - but I'd submit that even these are enriched by the use of traditional, standardized prayers, precisely because those prayers not only say something to God when placed upon our lips, but they also (more significantly) say something to us! By following even a simple prayer rule, one is being conditioned in the mentality held by those who authored those prayers. Formal prayers you'll find in prayerbooks are typically authored by Saints, who I think have something to teach us.
Something our parish Priest said which went against even my own instincts (and I definatly do not have a low-church or otherwise Protestant background - quite the opposite actually) was that when saying a prayer rule, you should fire through it. Yes, collect yourself together first - do your best to remove distractions, and be mindful about what you're reading, etc. But just go through it - kind of get bathed by what you're reading. IOW, prayer rules, and even liturgical prayers, are very much a matter of immersion and are meant to inform the soul over the long term. I had some skepticism about this, but I have to agree with the Priest that this is the way to go. It also seems to be my experience of Church matters amongst those for whom these things are not new (ex. being around for a Reader's service - the man barely stops to breath!)
In the end, prayer is for our sake - it's not a performance to impress God, or to get Him up to speed on something He isn't already aware of. He doesn't need that kind of "convincing."