We should much think about the devil. By thinking about him we give him importance and strength. We should think only of God who is everywhere and in everything. The devil would then be simply a mask of God. In other words all that hides us from our own deepest truth, all that covers our soul and prevents us from following the path shown by God through his incarnations and representatives.
Thus, for example, the devil is all that fills us with fear, greed, anger, agitation, depression and induces us to tell lies and turn away from things that are true, beautiful and divine.
Affectionately,
Alok Da