3 x 5 index cards layout help

[Zhorn]

So I've come across a few recommendations to use 3 inch by 5 inch index cards as a way of reigning in my prep-bloat for games, and was wondering if anyone had some good layout recommendations or systems of what information to cut back to.
Be it for npc's, item handouts, maps, room details, quests. Looking for anyone who has used an index card style of prep and what general approaches they've taken to get the most out of it.

One idea I've been batting around in my head is keeping a case of player related index cards that I hand out at the start of the game (along with some blanks for the players to add to) and collect up at the end of the session for general player goals, motivations, personal quests and such, where I can also add in insider information for particular characters between sessions (names of criminal contacts, results of downtime carousing or research, adventure hooks, etc).

[hymer]

We use index cards for magical items. They lay out the mechanics of the item, and the player who gets the item takes it and keeps it with their sheet. This is particularly helpful in D&D 3.5, with the huge amount of items and their often fiddly nature that needs to be kept track of.

[KillianHawkeye]

The only thing I use cards for is to keep a copy of vital PC stats and other notes on for reference purposes, and they double as initiative order cards during combat. I used to use 3x5" cards for this, but picked up some larger ones that I use now (I think they're 5x7").