"As for you, you were dead in your transgressions and sins, in which you used to live when you followed the ways of this world and the ruler of the kingdom of the air, the spirit who is now at work in those who are disobedient." NIV translation
By "you", Paul means all of us and we were dead spiritually (separated from God). The ruler of the air that he is talking about is Satan and it reminds us that there really is only two options; you follow Satan or Jesus and there is no middle ground.
There are many that have taken passages like this and put all of their effort into ensuring that they do not commit one sin or another but what "followed the ways" means is a thing of the heart. We may not commit one sin or another but would you like to? The only way we overcome any sin is through a change of heart and not by our own will power.
"All of us also lived among them at one time, gratifying the cravings of our sinful nature and following its desires and thoughts. Like the rest, we were by nature objects of wrath." NIV
Paul includes himself in this and says that we were following the cravings of our flesh. James also described this condition in chapter two of his letter contained in the Bible. It is easy for us, as people, to put some Christian leaders up on a pedestal and forget that they were once in this same condition. The really great leaders, like Paul, humble themselves and point out that they are a part of the "all of us" that he describes here.