While working up a load, I use small pieces of paper--one on the bench in the "Working Load" box, and another piece of paper that goes into the container with the cartridges. (Those baggies are a good idea.)
Once I determine the best load, pertinent information is noted on a 3x5 card and indexed in a recipe box. That box stays on my reloading bench. When loading for that cartridge, even if I know the specifics, I still put the card on top of the box where I can check it at ease.
Every box of cartridges is labeled--sticker on the box. When one walks into my cartridge storeroom, each load label is visible. I have sons, and enough cartridges that could cause problems if used in the incorrect firearm. The Boys are very good about checking everything--I'm thinking the system helps toward avoiding mistakes.
The reloading charts I've printed from the internet are indexed in a notebook. Surely helps in not shuffling and looking through papers. That notebook lives beside my loading manuals.
Had the idea last week to include my 3x5 information in the notebook, but haven't decided yet on a simple way to present it.
The methods the others have offered are fine also.