Anything else is a gamble. The games best defensive player, such as Gary Payton, Mario Elie, Stacy Augman, and Eddie Jones, get their 2 or 3 picks a game, but they rarely get beat defensively. Steal increase when you are mentally alert and looking for windows of opportunity. I would almost guarantee that you will have two or three passes a game fall into your lap without over exerting yourself if you just stay alert to the defensive end of the court on each possession. Responding to an event involves both reaction time and movement time.
Some players are alert for periods of time but inconsistent.
Alertness I believe has a lot to due with your heart and desire to be a good defensive player. Great offensive players are constantly looking for shot or drive opportunities. Conversely, great defensive players are always watching for doors of opportunity. Stay alert every possession. Position - Proper defensive technique and position give you more opportunities than just using your athletic ability.