Set aside specific times during the day in order to let your mind wander or your concentration drift. If you have a set time during the day — say your "drift off" time is at 5:30 every day, when you get back from school or work — you may be less likely to sanction drifting off during 11 a.m. or 3 p.m. If you catch yourself drifting off during any of the unsanctioned times, tell yourself that you have a designated drift off time and try to keep your brain concentrated on whatever task is at hand.