My barn is fairly organized, I think. Each bridle hook is labeled with the horse's name, stall number, girth size, and whether they need a riser pad/boots (if they have boots, then they're described on the label and can be found in the boot bin).
School saddles all have name plated on the cantle with a number which corresponds to a list that can be found on the wall next to the saddle racks. Saddle pads are separated into square and shaped and kept on shelves. The girths are arranged by size (so we have smaller than 42", 44-46, 48-50, and 52 and bigger) and each girth is also labeled with sharpie so you know the size.
Most riders bring their own grooming supplies but if not, then there are bins of school grooming stuff that are organized at the end of each day so that each bin has all the necessary grooming tools.
On our board in the grooming area there are instructions for how to groom/tack a horse (among other things) but beginner riders generally don't tack up without the supervision of my trainer or a working student (half of my job is getting the beginner kids in the arena and on their horses). Even if they do tack up on their own, everything is checked before they mount in the arena (aka, bridle adjustments and girth tightness/saddle placement).
Tack that needs to be cleaned gets placed on a hook in the middle of the tack room for people to do before/after they ride. I clean tack almost every time I'm out there...it's generally the working kids that clean the tack because we know how to (but anyone can do it if they ask to be taught how to)
It works pretty well, I think. The kids are all taught where to put their stuff when they're done and we all try to sweep out our grooming stall each time we use it so at the end of the day, there's not as much of a mess to clean up.