The SAT and ACT require hours of straight thinking. And, just as hours of anything can be, it’s exhausting. Therefore, you need to train your brain.
Training for the SAT/ACT thinking-marathon is like training for any marathon.
Start small. Try taking timed sections in pieces. Do 30 minutes here, 30 minutes there. Eventually, do an hour of work.
Brain endurance does not come overnight. Student MUST take a full-length exam before showing up to the real exam. Be it at the library, kitchen table, or proctoring service, all students should sit through a full exam to ensure that endurance, stamina and pacing are perfected.
Walking into a test cold is the same as attempting a triathlon without ever having worked out. It will exhaust you, and you most likely will not make it to the end without falling apart.
And, just as you would in any athletic competition – breath, refocus from time to time, and hydrate yourself during these exams.