You never know where inspiration will strike. You could be at work, at home or out with friends and you may see something that catches your eye. Something that give you an idea for your wedding.
To make sure that you don't lose that idea always have a pen and paper with you to jot it down. I would even keep a piece of paper and pen on your nightstand in case you get an idea in the middle of the night.
You can really use any notebook but I recommend one that has pages that are already pre 3-hole punched so you can easily add them to your wedding organizer.
I love the Planning Notebook by russell+hazel ($14) because the pages are 3-hole punched and perforated so they can be removed easily and placed in your wedding organizer. The notebook has 3 small rings on the binding so that you can easily store it in your wedding organizer too.
And if you're still shopping for the perfect wedding organizer, check out the one I wrote with russell+hazel. It really has everything you need.