You can customize the Finder's List View windows. Add and delete columns. Opt to show the size of folders. Change the size of icons.
Add and remove columns from the Finder’s List View windows on a Mac
How to hide (and show) Finder’s Favorites
Sometimes the Finder's Favorites disappear (this happens in iTunes also. Here's how to bring them back. Does not require programming.
How to name your Mac
Name your Mac, making it easier to find it when using file sharing or AirDrop. This is especially nice if your Mac used to belong to someone else. Make it yours by renaming it.
Minimize a Mac window by double-clicking its title bar
Minimize a window with a simple double-click in the title bar. It's easier to click the title bar twice than to click the yellow button once, because the target is so much bigger.
Did your Mac’s red, yellow, and green buttons change to gray?
Bring some color back to your Mac! If the Close, Minimize, and Zoom buttons aren't red, yellow, and green, check the System Preferences.
How to find the Mac’s Software Update options
Apple has moved the Software Update options again! Here's how to find them. It's important to know where they are so you can change them as desired.
Too many notifications on your Mac? Turn some off.
it's nice to be notified of important stuff but too much is too much! Here's how you customize Notifications, on an app by app basis.
Set priority for WiFi networks so your Mac joins the right one
You can set the priority for WiFi networks! This way, you always join the right one, not some sketchy free, open network.
Bring back the scroll bars
Scroll bars should show! They're important indicators of how much material remains unviewed. Apple turned them off; we're turning them back on.
Stuff the cat did: toggled VoiceOver so my Mac started talking
Your Mac can talk to you, telling you which button you're about to click, which menus are showing, and so on. Very handy if you can't see well, but very surprising to have it turned on by itself. Or by the cat.