How do you organize your story?

My last story was laid out quite well, in my mind, and I didn’t spend a lot of time organizing my writing.  It worked fine, I think, and I did use an index card system, and a notebook to write down random ideas to put in the beginning, middle, and end areas.  So how do you plan out your stories?  On the computer?  In notebooks? Plotted on big paper?  Do you use graphic organizers or story maps of some sort?  This next story needs more time spent on planning before I write, so I’d love to hear how you do it.  I’d like to have a great system, so I’m not ripping out my hair wondering where the heck I stuck that Post It note that had the great idea on it!