- Ctrl + Cmd + Shift + 4 will let you take a screenshot of a region of your screen and copy it to the clipboard. It can then be pasted directly into most applications, from email clients to chat clients. No random screenshots sitting around. If you want to capture a whole window, press Space after the initial shortcut, then click the window.
- While a menu is open, hold Option; if you're lucky, you'll get some additional options. This works after right-clicking an item in Finder, for example, or after right-clicking an icon in the Dock.
- Magnet for window management. This is a third-party application, but you'll wonder how you lived without it. If you've used Spectacle, Magnet is similar, but I find Magnet to be a bit more graceful.
- Sidecar and AirPlay. Want a second screen? Got an iPad or Apple TV? You can effortless treat it as a second screen with very low latency. It "just works."
- Cmd + Space to open Spotlight. Most power users are already familiar with this; if you're not, try it.
- Cmd + Shift + G in Finder to go to a folder by path. You can also use it to copy the path to the current folder.
- Return/Enter to rename the currently-selected file in Finder. If you're coming from Windows/Linux and are accustomed to pressing F2, you might not know about this one.
- Similarly, to open the currently selected item in Finder, press Cmd + O. To navigate up a directory, press Cmd + Up.
- Ever installed a new drive in your Mac? You don't need to manually download macOS installation media beforehand; with the right key combination at boot, you can install it via the internet. There are a few different related combinations with differing functionality; it's worth looking them up and choosing the right one for your situation: https://support.apple.com/en-us/HT201255
- While a menu is open, hold Option; if you're lucky, you'll get some additional options. This works after right-clicking an item in Finder, for example, or after right-clicking an icon in the Dock.
- Magnet for window management. This is a third-party application, but you'll wonder how you lived without it. If you've used Spectacle, Magnet is similar, but I find Magnet to be a bit more graceful.
- Sidecar and AirPlay. Want a second screen? Got an iPad or Apple TV? You can effortless treat it as a second screen with very low latency. It "just works."
- Cmd + Space to open Spotlight. Most power users are already familiar with this; if you're not, try it.
- Cmd + Shift + G in Finder to go to a folder by path. You can also use it to copy the path to the current folder.
- Return/Enter to rename the currently-selected file in Finder. If you're coming from Windows/Linux and are accustomed to pressing F2, you might not know about this one.
- Similarly, to open the currently selected item in Finder, press Cmd + O. To navigate up a directory, press Cmd + Up.
- Ever installed a new drive in your Mac? You don't need to manually download macOS installation media beforehand; with the right key combination at boot, you can install it via the internet. There are a few different related combinations with differing functionality; it's worth looking them up and choosing the right one for your situation: https://support.apple.com/en-us/HT201255