Three things. About 25 minutes. That's the whole job.
Studying 25 minutes every day beats 4 hours once a week. Your brain needs repeated visits, not one long one.
Every subject is marked on precise English sentences — even Pakistan Studies and Islamiyat. Ten minutes a day compounds over years.
You forget most of what you learn within weeks unless you revisit it. That's normal, and the fix is revisiting on schedule.