if you're going to have to sit down and power through a task that will take you a long time (cramming for an exam, a weekend marathon coding session, etc), oper

if you're going to have to sit down and power through a task that will take you a long time (cramming for an exam, a weekend marathon coding session, etc), operate in cycles of 20-30 minutes of focused work and then 5 minutes of something unrelated (preferably something entertaining/distracting/social). your mind will stay sharper, it'll be easier to focus, and you'll last longer before you burn out.