1/ Change the default web browser in macOS Sierra — If you prefer another web browser to Safari (which I find excellent), you can change the macOS default. From the Apple () menu, choose System Preferences, then click General.
Choose your web browser from the ‘Default web browser’ pop-up menu.
2/ Set your default printer — If you have more than one printer, one thing you could do to make them slightly less annoying, though, is to choose which one to set as your default. If you print to a particular device way more often than another, it makes sense to always default to the last one you used when you choose File > Print.
Choose System Preferences from the Apple Menu at the top-left of your screen, and then click on Printers & Scanners.
You’ll see a list of your devices on the left, and you can pick which one you want as the default from the drop-down near the bottom of the window. Close the System Preferences window, and when you print something afterwards, your Mac will assume you want to use the device you set as the default.
You can click the drop-down show to temporarily switch to a different printer if you need to, but it will always revert back to the default for the next job.
3/ Move the cursor with your keyboard — If your mousing hand needs a break, or perhaps you need to move the mouse pointer one teeny-tiny pixel at a time, there’s a way to move the Mac mouse pointer with the keyboard rather than nudging the mouse or swiping your trackpad.
Turn on the Mac feature called Mouse Keys, which lets you move the Mac mouse pointer by tapping the keys on your numeric keypad or, if you don’t have a separate numeric keypad, by pressing a set of keys within the keyboard itself.
Open the Mac’s System Preferences by clicking the Apple menu in the top-left corner of the screen, select System Preferences. Click Accessibility, select Mouse & Trackpad in the left column, then check the Enable Mouse Keys checkbox. This lets you move your mouse pointer using a numeric trackpad: press the 8 key to nudge the Mac mouse up a tad. The 2 key will move the mouse down, while the 4 and 6 keys move the mouse left and right, respectively. The 7, 9, 1, and 3 keys move the Mac mouse up and to the left, up and to the right, down and to the left, and down and to the right. (There’s more on this at Here’s The Thing.)
4/ Force the Finder to restart in macOS Sierra — Represented by the blue icon with the smiling face, the macOS Sierra Finder is the home-base app for your Mac. You use it to organise and access almost everything on your Mac, including documents, images, movies, and any other files you have. However, sometimes you need to restart it if it’s acting up or if you’ve installed an app that requires a restart. To do so: in Finder, click the menu and hold down the Shift key on your keyboard.
Click Force Quit Finder.
You can also hold down the ⌥ (option) key on your keyboard.
Click on the Finder icon in your Dock.
Choose Relaunch from the bottom of the pop-out list that appears.
5/ Search Google directly without even firing up a browser — You can use your Mac’s Spotlight to directly search using your default search engine. Type something in Spotlight that you want to search on Google, then, press Command (⌘) + B. It will open Safari with your search term…