I'm a student and I got my iPad about a week ago. Since I'm trying to go paperless for the most part I found that it's pretty hard to keep my files organized, especially since I'm still trying to find out which apps are best suited to what tasks. For example I'm currently doing most of my notes in Evernote since that app allows me to write things down, add images and draw freely whenever I need to (like when copying stuff from the blackboard). For exercises I use Word because it has more text formatting features. I'm still figuring out maths as it's pretty complicated to write down equations with either a keyboard or my finger. The best thing I could come up with is using MathPad to generate an image and then pasting that into Evernote for each equation that I need to write down. For other tasks I use the fitting MSOffice apps.
Anyways, since I only have the 32GB iPad 2017 I want to archive my documents in OneDrive. I found that using all those different apps, along with the occasional handwritten pages and worksheets that I need to scan my current file system of one folder per subject is likely to get cluttered throughout the year. How do you organize your files?
I'm looking forward to any advice you could give me.

I have a folder for each subject and store there but now i am using online cloud storage. Its better than storing on physical drives.

I would make a directory structure like this, by topic, then by class:
Math
Math\MTH100\
Math\MTH101\
CompSci
CompSci\CSI101\
CompSci\CSI110\
CompSci\CSI120\


I would probably use a Wiki type note-taker too like Tiddlywiki at TiddlyWiki

— a non-linear personal web notebook. It's free, and it can live on your flash drive, or on a free service called Tiddlyhost. Tiddlyhost means you can access the Wiki from any browser, any computer.



Don't forget to back up all your files each week at least.