There are various dimensions of what people often call “spiritual warfare,” but one dimension we sometimes miss is the mundane, day-to-day way we treat each other and walk with God … things like truth, justice, faith, sharing our faith, and so forth. That is, some of the very things that Ephesians 6 discusses when it talks about the full armor of God.
I wrote a fuller essay on this subject–longer than the normal blog post here–for a book edited partly by my friend Rob Plummer of Southern Seminary. The essay is available free at the following location (as well as some other references on the internet):
http://www.thegospelcoalition.org/blogs/justintaylor/files/2013/02/Keener-chapter-from-Pauls-Missionary-Methods-2.pdf
Although I touch on some other elements of spiritual warfare, I emphasize here the practical, day-to-day dimensions involved. Of course, I still have much to learn in practice; but I believe you will find the Bible study helpful.