I don't know how to sleep? Help?

I honestly don't know how to sleep!I'm constantly tossing and turning to find the perfect position. My mind is always active and I can't get out of my mind. My Dad once said that I just need to stop thinking but HOW do I do that?? I don't have the patience to just hope I will fall asleep! I always end up getting lost in my thoughts and forget that I was even trying to sleep. How have I survived this long with these issues you may ask? I usually take antipsychotic medication to knock me out so sleeping without them is pretty much learning how to sleep all over again. I always had troubles sleeping before using meds. I always wake up at least 30 times and sleep would last no more than 4 hours in total in a 7 hour time frame.

EDIT: So I managed to sleep for a few hours this morning after listening to an audio book for a few hours. I took some of my medication for my blood pressure and it helped me sleep for that few hours but it was long enough to recharge me. Although I did spend so many hours trying to fall asleep in the first place so I got 3 hours in a 10 hours timeframe.