Unload your mind before you go to sleep. Try to avoid working or sending emails right up to the time you need to switch off and instead, set yourself a deadline (maybe 10pm) by which time you’ll have got all your chores done. Anything left undone by this time simply gets written down on list of things for the morning. This gives you some mental downtime before going to bed, and you can ‘park’ all those niggling thoughts that might keep you awake.