This tip is one that I've been using for a long time now. I simply keep some tote bags on the back of the door to my sewing room. Each bag is designated for a guild or sewing group. Any time anyone asks me to bring them something, or I need to remember to take something to that meeting, I put it in the bag. That way, when I grab the bag before I leave, everything I need is already there! No last minute running around trying to find stuff. I also put my show and tell quilts in these bags (that's why they are so large.) It's just another small way to stay organized.
Now I'm not saying that I've NEVER forgotten to bring something I was supposed to have to a meeting, but I do much better with this method than trying to use my brain to remember.