1/ Use a keyboard shortcut for display mirroring in Mac OS High Sierra — Display mirroring is when your external monitor and laptop display show the same screen, instead of dividing the view between. The shortcut to the System Preferences > Displays > Arrangement > Mirror Displays command is Command-F1, which turns display mirroring on and off in macOS High Sierra.
2/ Use Night Shift in macOS High Sierra — macOS High Sierra has Night Shift, a feature brought over from iOS. It helps you reduce the amount of blue light you’re exposed to during the evening by shifting the display of a Mac to a more yellow tone, which is supposed to assist you later, together to sleep. The proliferation of electronics with screens, as well as energy-efficient lighting, is increasing our exposure to blue wavelengths, especially after sundown, and this may affect sleeping patterns.
Open the System Preferences app.
Select Night Shift.
You can turn Night Shift on or off. Set it to come on from sunset to sunrise — or you can use the Customize options to implement it for the hours of your choosing.
You can also adjust the colour temperature via a slider, but warmer settings may affect the appearance of some onscreen motion.
3/ Disable Split View in Mail — For those who use Mail in full-screen mode, you may have noticed that High Sierra now defaults to a split-screen view when you’re composing a message or when you’ve double-clicked on an email to open it in its own window. If you’re not a fan of this, it’s really easy to disable. Choose Preferences from the Mail menu at the top of your screen, then click on the General tab. ‘Prefer opening messages in split view when in full screen’ is the checked box, so uncheck that box. When you do so, Mail’s full-screen mode reverts to its previous behaviour.
4/ Block Cross-site tracking in Safari — Apple promised a way to block websites from cross-site tracking in Safari in macOS High Sierra and iOS 11. The idea is that you won’t see ads for a product you just looked up when you on, say, a news site. If you’re still seeing ads like that after upgrading to Apple’s new operating systems it’s easy to see if preventing cross-site tracking is really enabled.
Launch Safari on your Mac
Go to Safari > Preferences from the menu bar
Click the Privacy tab
Check ‘Prevent cross-site tracking’
(This is also where to find the ‘Ask websites not to track me’ setting.)
You can do this on iOS, too. Prevent Cross-Site Tracking in iOS 11 involves a trip to the Settings app, under Safari.
5/ Show full website addresses in Safari — Starting around OS X Yosemite, Apple has chosen to have Safari hide full website addresses by default. Instead, it only shows a basic name domain in the field at the top of browsers.
Go into Safari preferences by pressing Command (⌘) + Comma, or from the Safari menu, choose Preferences. Click on the Advanced tab at the far right.
The first menu item you’ll see is the Smart Search Field. Check or uncheck the box to turn the feature on or off: checking the box will show the full URL.
This lets you quickly see which part of a website you’re in.