Using the Mind Palace is basically a relaxation technique so long as you lead whilst walking around your palace. You can also imagine walking into a nice peaceful garden and all the things you can see there. You definitely should NOT go on the computer or watch loads of tv straight before bed because this makes it hard to go to sleep, the light fro. The screen disrupts our sense of it being nighttime.
Also you are a teenager. It has been proven that teenagers and young adults are in a permanent state of what is like jet lag. Sleeping late in the day and then being awake until the early hours. If it's any consolation you do actually grow whilst you are asleep ( if you are young, not just a middle-age spread adult! Lol)
For those with disrupted sleep patterns it is important to try and reset your body clock. Otherwise it is like you are in jet lag continually. Any one who has had jet lag will know what I mean ( actually my son is still in jet lag from returning from Canada on Tuesday!) . You need to make yourself get up at normal times, even if you are tired, eating at the proper time really helps too.
Avoid caffeinated drinks, certainly after 6pm. Also avoid eating sweet sugary foods late in the day. Try a nice warm bath prior to bedtime. Do not have a late nap in the day. If you do nap it should not really be longer than 1 hour in length.
Remember, different people need different amounts of sleep. Sir Winston Churchill and Margaret Thatcher, for instance needed very little. However if your lack of sleep affects your ability to function then it is a problem.
Personally, I would say the worse things keeping you awake are stress, when you lie awake worrying a bout things. I now just tell myself there is no point worrying and to put worries into a box and put it away. The other really good way of making you stay awake is to really, really, TRY to go to sleep, this just doesn't work.
Reading a book usually works really well.
Finally, when you sleep try to do this in bed (unless you are on holiday on a sun lounger!) rather than in a chair or on a couch, that way you are conditioned to associate bed with sleep.
Hope this helps!
---------------------------------------------------------------------------------------------------------------------------------------------
Don't make people into heroes John. Heroes don't exist and if they did I wouldn't be one of them.