If you wake up because you are stressed about something, keep a notebook and pen by your bed so you can jot down some notes to yourself before going back to sleep. Your brain may be waking you because you are worried you might forget something on your agenda the next day.
If you sleep in a room with or near your computer, turn it off before falling to sleep. The blue light of the power button or the glow of the screen prevents may people from getting a good night's sleep. Your room should be dark to help you stay asleep.
Also, if you have wireless devices, cell phones, a router, etc., make sure you turn them all off before bed and don't keep them on your nightstand or even in your room if you can help it because they emit RF radiation that could interfere with your normal brain activity.
And, lastly, check the outside of your home or apartment building to determine if your power company has switched you to a new "smart meter." If so, you will want to be sure your bed, esp. the head of your bed, does not share a wall with the smart meter. They can transmit data continuously and the signal may be strong enough to cause interference with your sleep habits.
Good luck! Oh yes, and if you take daytime naps, STOP, because that will make it much harder to sleep through the night (or at least that is how it works with my 5-year old! ha ha!).