Hello, and thank you for your question.
I am sorry to hear that you are having difficulty sleeping at such a young age. Although it is not that uncommon today.
First, If it is thought that you might be having any difficulty breathing at night, consider sleeping on your back with your head of the bed up slightly, as this can assist your airway and lungs to remain open and to expand more easily
Off the top of my head, good sleep hygiene includes:
Limiting naps to no longer than 30 minutes during the day.
Do not eat a large meal up to 2 hours before going to bed at night (it is ok to have a very light snack)
Do not exercise in the few hours before bedtime (but DO exercise vigorously during the day - of course if you are not in the habit of exercising, start by walking and work up to running, cycling, swimming, rowing, or other aerobic activity. This will also strengthen your heart, as well as help to 'use up' any stress hormones such as adrenalin that you secrete during the day and that can make it hard to sleep.)
Don't drink much water or other fluids in the two hours before bed.
Don't drink alcohol, more than one drink in the evening. While alcohol can initially help some people to go to sleep, it causes one to have a light sleep pattern, thus sleep is not refreshing.
Our body and brain were at one time accustomed to being aroused by light in the morning and to being 'shut down' at night by darkness. Artificial lighting disrupts the natural signals that our brain developed to respond. Lighting stops the hormone melatonin which is released by the pineal gland in the brain from being released. Besides considering taking a supplement of melatonin, begin decreasing light sources in the hours before bedtime (turn down the lights, don't sit by a bright lamp). This includes not viewing the TV or the computer screen, as this type of lighting is very stimulating. In fact, any intense intellectual, emotional, or physical activity will make it difficult to go to sleep when engaged in the hours before sleep. So it is recommended that you do not read any thing stimulating or watch the news, etc. Instead consider putting on calm music, and/or taking a warm bath, doing relaxing yoga or deep breathing exercises.
It is also suggested that the bedroom be kept only for sleep. This helps to signal the brain that when you go to bedroom it is time to shut down.
Additionally, consider waking up to natural sunlight. If you are able to open curtains so that sunlight will trigger arousal through the pineal gland (light falling on the eyelids will trigger the arousal hormone, DHEA to be released by the brain, and it will be easier to wake up and feel energetic). If your bedroom is not arranged for this to be possible, you might want to consider purchasing a full spectrum light to turn on near you head in the morning.
Of course, stimulants such as caffeine should be decreased if you have any sources after 12 noon.
For more good information on sleep and how to enhance you will find this link helpful: SLEEP
I'm standing by to clarify or reply to any additional questions about this you may have.