Try to ease into the habit of becoming more aware of the events and world around you. Reality checks are a useful tool, but I have also read a lot of accounts of them failing at the worst possible times. I would get in the habit of doing reality checks by some means or other, and backing them up with awareness. To get in the habit, I have set up a program that pops up with a little reminder every 15 minutes or so on my computer. (The program is called Stickies, by the way.) As for awareness and reality checking, if you carry a watch, any of the watch methods above would work great. You could also leave tangible sticky notes lying around or draw a letter/symbol on the back of your hand. It will become easier to do as you get into the swing of things, too.

Good luck!