How to Organize with Subfolders in OS X El Capitan
You can put folders inside other folders in OS X El Capitan to organize your icons. A folder nested inside another folder is a subfolder.
You can create subfolders according to whatever system makes sense to you — but why reinvent the wheel? Here are some organizational topic ideas and naming examples for subfolders:
By type of document: Word-Processing Documents, Spreadsheet Documents, Graphics Documents
By date: Documents May–June, Documents Spring ’12
By content: Memos, Outgoing Letters, Expense Reports
By project: Project X, Project Y, Project Z
When you notice your folders swelling and starting to get messy (that is, filling with tons of files), subdivide them again by using a combination of these methods that makes sense to you. Suppose that you start by subdividing your Documents folder into multiple subfolders. Later, when those folders begin to get full, you can subdivide them even further, as shown here.
Allow your folder structure to be organic, growing as you need it to grow. Let it happen. Don’t let any single folder get so full that it’s a hassle to deal with. Create new subfolders when things start to get crowded.
If you want to monkey around with some subfolders, a good place to start is the Documents folder, which is inside your Home folder (that is, the Documents folder is a subfolder of your Home folder).
If you use a particular folder a great deal, put it in your Dock, or make an alias of it and move the alias from the Documents folder to your Home folder or to your Desktop to make the folder easier to access. Or drag the folder (or its alias) to the Sidebar, so it’s always available, including in Open dialogs and Save sheets. If you write a lot of letters, keep an alias to your Correspondence folder in your Home folder, on the Dock, on your Desktop, or in the Sidebar for quick access. (By the way, there’s no reason why you can’t have a folder appear in all four places, if you like. That’s what aliases are for, right?)
If you create your own subfolders in the Documents folder, you can click that folder on the Dock to reveal them, as shown here.
It’s even more convenient if you choose to view the Documents folder as a list.