The most common sleep problem for teens is not that you cannot sleep. It is that you are trying to. Sleep is one of the few things that gets further away the harder you chase it, because effort means alertness, and alertness is the opposite of what you need.
There is also biology working against you. During your teens the body's internal clock shifts later, so genuinely feeling sleepy at 10pm can be difficult even when you are exhausted. Then school starts at 8, and the gap comes out of your sleep rather than your schedule.
So the goal at 1am is not falling asleep. It is being calm and bored. Calm and bored is where sleep tends to show up on its own.
Start with the mental math, because that is usually the loop. 'If I fall asleep now I get five hours' is a calculation that raises your heart rate every time you run it. When you catch yourself doing it, say the sentence that is actually true: a rough night is survivable, and tired-but-fine is a real state you have been in before.
Then clear the queue. Keep paper near your bed and write down everything your brain keeps handing you — the assignment, the text you did not send, the thing you said in third period. Your brain rehearses things because it is scared of losing them; on paper they are safe until morning.
If you have been lying there more than about twenty minutes and you are frustrated, get up. Low light, somewhere that is not your bed, something quiet and slightly dull — not your phone, not a series you are into. Go back when you feel heavy. This keeps your bed from becoming the place where you lie awake and worry, which is a habit your brain learns quickly.
For the body: long exhales, unclench your jaw, let your shoulders drop away from your ears, warm feet. Scanning down through your body slowly is not magic, but it gives your attention something to do that is not the future.
And in the daytime, the two things that help most are boring: light in the morning, and roughly the same wake-up time on weekends. Sleeping until 2pm on Saturday feels essential and pushes Sunday night out even further.
If you have been struggling to sleep most nights for weeks, or you are falling asleep during the day, tell an adult and let a doctor look at it. Persistent sleep trouble is common and treatable, and it is worth more than another list of tips.