When thinking about topics like spiritual warfare, I often like to think back to the Screwtape Letters. Screwtape gives Wormwood specific advice on how to subvert man and so ensnare the soul.
I often think christians lack a deep understanding of the nature of warfare. We have this viewpoint that if we have good intentions and a light in our hearts, then we can do no wrong. How niave. While striking against the enemy anywhere may not return void, this doesn't mean that it will produce the most beneficial results. Christians are soldiers with Christ as our General, the Father our Commander in Chief, and the Spirit acting as our communications officer.
Where am I going with this? Well I've read two very good posts that you could look at as briefings on the tactics of the enemy. This is how the Devil fights. It is vital intelligence on how he leads us astray.
The first is Feeble Knees's Baby Christians and Decoys. In it she discusses how the good intentions of young christians are lead astray by providing them with a responsive individual in need of their help. However ultimately this person is a decoy. They are using the Christian for emotional or physical support while absorbing their time, time which could be put to better use with others they should be far closer to like their friends and family.
In the end the decoy doesn't come to any lasting faith. The family and friends of the young christian are left with a horrible impression of God because he took away their loved one and gave them to a stranger. The young christian's faith is damaged because she worked and prayed so hard, yet had no results to show for it. It is bait that so many people take.
The second is Joe Carter's discourse on theological arguments. Joe discusses arguing over the desire to prove the existence of God and the need for Christ to others. To the Christian it seems possible to argue someone into faith. To impart the understand of God into them through reason alone. If only you can come up with a better argument or a stronger proof, then that person will have faith and believe.
In the end this is futile. While sharing our knowledge of God is a good thing, you can't argue someone into faith just as you can't beat them into it with a Bible or with peer pressure. Only God can restore a person's soul. Arguing has a purpose (which is the real topic of Joe's article), but sometimes it is far better and more productive to pray that God will work in someone from the inside rather than trying to work upon them from the outside.