"Post-It" notes are great. You write little notes on them and you stick them on the fridge, in your book, or on your computer screen to remind you of things. Since I spend a few minutes regularly in front of the computer every day, I find that my computer screen is the best place to put reminders on.
Now, instead of writing notes on little pieces of Post-It notes, I have re-discovered the Stickies software, which I used to have on my computer years ago. It is one of the most useful little programs you can ever install on your computer. The bright yellow box on which you write a reminder to yourself stays pinned to your screen. It stays right on top of every window you have opened up. This new Stickies software also has a lot of features which I am not sure I'll ever use. You can choose a different colour for your Sticky, you can make it not always go to the top of your windows pile, you can change fonts, set opacity, set reminders, sleep mode, etc, etc. It is just a very simple to use program, elegant, and free.
If you are interested to try it out, download this program from: http://www.zhornsoftware.co.uk/stickies/download.html