St. Simeon the New Theologian gave some insights into prayer. There is a “holy vigilance” that needs to take place. We don’t just walk into prayer, so to speak. We are to give attention to the life of prayer.
Attention should be linked to prayer as inseparably as body is linked to soul. Attention should go on ahead, spying out the the enemy, like a scout. It should be the first to engage sin in combat, and to oppose evil thoughts entering the soul. Prayer should follow in its wake, instantly exterminating and destroying all the evil thoughts with which attention has been battling beforehand; for attention alone cannot destroy them.
Pay attention in prayer! It is a battle and the enemy wants us on the sidelines.