Here's a two-for-one:
Use a big binder clip to keep your keys together;
Use it to clip reminder notes where you need them; or
Do both at the same time.
For those of you who don't use pockets, if you always clip the keys to the same place in your bag, you'll always find them without rooting around for five minutes while your friends stand around wondering how someone as smart as you are can go through the same effort many times every day without figuring out something so basic as keeping keys somewhere easy to locate.