howto identify sleep killers

do you have imsomnia, you cant sleep at night? averagely you should sleep for 8 hrs as an adult.many things cause this but we also have to look inwards;if you have a big day tommorow,do you take coffee after a sleepless night ? how do you feel at bed time? is it anxious tense and hoping for morning to come?what do you think about lying in bed do you talk with your spouse or make calls?what do you do when sleep doesnt come? do you use exercise to tire yourself.
finally how do you prepare for night?
adjust these areas and find yourself sleeping deeply and consistently in the future.