Mac OS offers many useful tricks that a lot of users don't know about. Here are four of my favorites.
Partial print screen
Usually, when people print their screens, they print their entire desktop – with your embarrassing tabs open and all. Mac has a pretty nice feature to get around that problem: "Print Partial Screen". To print a specific part of your desktop, just hold down command+shift+4 at the same time. When you do that, a target will appear with which you can select the screen you want to be captured.
If you want to keep your dock visible on the screen without disappearing, hold down command+alt+D. This function will fix your dock. If you want to reverse the command, just hold down command+alt+D again.
Quickly alternate between applications
You can use command+tab keys to alternate between your open applications. You can also use this function to close any open app: hold down command+tab+Q. You can also minimize an app using command+tab+H.
You can also alternate between apps using F3 – all the running apps will show up on your screen and you can select the one you want to navigate to.
Use Spotlight as a calculator
Sure, you use Spotlight to try and find your files or quickly access certain applications. But you can also use it as a calculator. Put in simple algebraic and Spotlight will automatically solve them – for example, if you type in 4+4=, it'll show 8 as the result.