A Living Sacrifice
Offer your body up as a living sacrifice to God. Let your mind be transformed by God and you will know what is right.
As a Christian, I found this very good advice. God is out there, just open yourself up to him and you will become a better person. He will change your mind when you are wrong and reinforce your ideas when you are right. What could be better.
The problem, as I see it, is if God doesn't exist this is very dangerous. If there is no God, then what is prayer? It is simply thinking on your own. If you have some crazy idea and you pray on it, and after praying on it it still seems like a good idea, then it suddenly has God's backing. How much harder will it be now for your mind to be changed?
The crazy thing is, if God is real, and he is good, and he actually communicates with us, then this seems like a pretty good thing to do. Suppose you have some moral quandary, who better to ask than the perfectly good, all knowing God?
One last comment here, just the language being used, offer your body up as a living sacrifice to God. This seems like a good answer to the question of "Even if God isn't real, what have you lost by following him?" This often comes up when discussing pascal's wager.
Gifts of Grace
We should not think too highly of ourselves, but be happy with the position we are in through faith in God. We all work together as parts of the body of Christ. We each have different gifts and we should play to those gifts.
This generally seems like a good way to build a society. If you are naturally a good teacher, be a teacher, if you are naturally a good leader, lead, etc. If everyone plays to their strength we will have a stronger society in general and we will all be better off.
The first part about not thinking too highly of ourselves, to me that can be taken a couple ways. My first thought when reading it was something along the lines of "don't be an arrogant prick". Don't think you are better than everyone else basically. This seems like a very good thing to me. People who think they are better than they are can get quite annoying.
On the other hand, it also seems like it could be seen as something to keep the common folk in line. If you have a menial job that you hate, the message might look like "that is where God put you, know your place and keep doing your job." I don't like this at all. Not that there is anything wrong with having a menial job, but it's always nice to imagine you have the possibility of moving up in the world.
Marks of the True Christian
Basically a big list of good things to do, love each other, help each other out, these sorts of things.
Something I found interesting is it includes to try to be peaceful with everyone, and to never avenge yourself and let God be the one who is vengeful. Instead give your enemy food and drink when he is in need. Perhaps I am just showing my bias here, but it seems that this message is pretty anti-war. And yet it seems to me that in america at least, a great many Christians are pro-war.