a living sacrifice to show ourselves as being one called to god to put off the sinful nature and live by the spirit....we are not to live in sin as the world does, but to lead a life that is worthy of the calling god has called us to do.....in other words give up sin and live for god.follow the straight path.....now does this meen we will no longer sin, heavens no, but we can be forgiven and learn, god will show us his grace we are saved sinners no longer lost sinners! 

You have to put everything, even your own body on the alter. If God wants you to give up something, give it up. If God tells you to go north then go north, etc. Yes, you can't really read verse one and exclude verse two, because they are one thought. Put your flesh into subjection. For if we be Christ's then we are crucified with Him.

Knowing this, that our old man is crucified with him, that the body of sin might be destroyed, that henceforth we should not serve sin.
For he that is dead is freed from sin.
Now if we be dead with Christ, we believe that we shall also live with him
Romans 6:6-8 

To me this verse says that we have to give our lives to God. I don't think that means we need to go and die for God, unless he says to, but that we need to give all our thoughts, wants, actions, and every aspect of our life to him. All of who we are needs to "die" so God can live in us. When we recieve Jesus, we are new. We have died to ourselves. I think verse 2 means that we need to not be like the world, but be totally changed. Hope that helps.