One of the most common causes for staying awake at night is a combination of the following two - stress, and a busy mind.
Although both of these things can go throughout the day almost unnoticed, once we start to slow down, all the activity in our mind can often seem to suddenly explode the moment we close our eyes.
Thoughts, images, feelings, and ideas that we have had from the day often will present themselves to us, in a hectic swirl of activity, often making it very difficult to relax- let alone get to sleep!
If this sounds a bit like you, then worry not - this is a totally normal reaction our mind is having to the activity of the day. However, you might sometimes find that this is getting in the way of your sleeping, which on top of the mind-chatter, can lead to a stressful night of worrying.
"11:30, still not asleep. Why can't I sleep? Oh no, it's 1am... only 7 hours of sleep left... why can't I get to sleep? I'm going to be SO tired tomorrow - and it's a busy day so I NEED my sleep! WHY CAN'T I SLEEP?!"
By this point it's pretty unlikely that you're feeling relaxed...
The main thing to do when you start to notice your mind doing this is to just become aware of what's happening. Notice it like you're watching from the sidelines, without becoming too immersed in it. Try not to 'follow' a particular train of thought, and put your focus on the flow of your breathing in & out, and the feeling of the heaviness of your body, sinking into the mattress.
Just allowing yourself to have a busy mind - without stressing about it - is one of the best things you can do for your night's sleep.