Hi Hope,
I too must be the most unorganized person in the world. I loose everything, I mix up everything... I make notes, put them in bags, loose them, and so on. you know what I'm talking about!
I bought myself a whiteboard (thanks Traveler 
) that I put against the wall in my kitchen (can't miss it like this, I walk passed it so many times per day). I write everything down on it: groceries, reminders, appointments, etc - when I go grocerie shopping, I take a paper and make a list of what I need to buy (copy it from the whiteboard) - when I get back, I erase what I was able to find.
There's also a large family planner like calender next to it to keep up with my medication.
Sticky notes don't work for me either, they don't stick well/long enough...
When I'm at work, I clean out my handbag and pockets, take out all papers, look at them and throw away what I don't need anymore.
I've been trying to organize my house: bought all sorts of plastic containers, and put all related things together (office stuff, decoration stuff, sawing stuff, etc) - bought files too (put all invoices in 1, all medical stuff in another, etc).
When I clean up, I take out the plastic containers I need and sort everything out.
And I have a 'storage' room for urgent situations - I put everything in there that I can't handle myself, when I have visitors, etc - once in a while I clean it out. And more importantly: that particular door stays closed for all visitors - LOL
The more I stress about my organizing skills (or lack of), the more I loose and forget... The 'storage' room is a perfect destresser! 