How can I improve my deep sleep?

I usually sleep 7 to 12 hours a night but rarely feel completely well rested and always feel groggy when I wake up. Did at at home sleep study but it came back normal. My deep sleep fluctuates between 10 minutes and like an hour and a half.

I usually sleep 7 to 12 hours a night but rarely feel completely well rested and always feel groggy when I wake up. Did at at home sleep study but it came back normal. My deep sleep fluctuates between 10 minutes and like an hour and a half.