I try (note, I said try) to do this every night before I go to bed because I am the world’s worst over thinker. I don’t have any specific methods like those mentioned above, but just try to think of things that relax me, which then (most of the time) leads to me drifting off to sleep.
At work I have found that I like using the different tools of Outlook and Outlook calendar to keep my mind as uncluttered as possible. As first I bucked against the idea, thinking my memory was sufficient to keep track of everything. I do have a very good memory, but I have now found that using Outlook calendar or something similar frees up your mind from constantly remembering everything you have to do. When my boss gives me a task that is not a one time thing but something he wants done every week, month, etc., I set up the event for the appropriate recurring time frame, and get a reminder when it’s time to do it again. This way I don’t have all of these random tasks floating through my head. Of course, most of the time I remember before the fact that it needs to be done, but when things get crazy, it’s good to have that backup reminder.
It’s funny, because various people at my job compliment me all the time for always getting my paperwork turned in by the deadline…and then I tell them that it’s mainly because every Tuesday (or whatever day), I get my reminder at 8:30 am to do such and such.