u/Key_Illustrator_2963

Hii everyone, I am a student currently studying for my exams. One thing i want to do to improve my focus and retention is to get 8+ hours of sleep in a single stretch. Previously i was just taking 6-7 hours of sleep during night and that makes me feel bit kind of anxious and lazy, sleepy during afternoon, so for years i just divided my sleep schedule into two intervals 6-7 hours during night and 45-60 min during day but this pattern is very destructive to my study . The problem with me is when i try to sleep for 8+ hour in a single stretch i somehow gets wake up at 6-7 hour mark and again feels sleepy duting the day, i have tried to remain awake during the day still i wake up just after 6-7 hour of sleep, that's make me very much frustrated. I sleep in pitch dark room with curtains, i don't do anykind of ritual prior to my sleep, what should i do to achieve a single stretch sleep for 8+ hour . Mattress? Exercise? Sleeping position? Nutrition? Or anything which can you recommend me to maintain a good sleep hygiene . Thank you