OS X has all kinds of great little features, but so many of them don't make the back of the box. Whether you've been an OS X user for a long time or you're new to the operating system, here are a few of the best built-in tools you might not know about (or you've just forgotten).
Optimise Your Wi-Fi Network with the Diagnostics Tool
Unless you've had problems with your Wi-Fi network, you've probably never seen OS X's Wi-Fi Diagnostics tool. That's because it's hidden away. To get it, Option-Click the Wi-Fi signal in your menu bar and select "Open Wi-Fi Diagnostics". This brings up a help wizard that you can ignore. On Mavericks, hit Cmd+2 to open up the diagnostics tool. On older versions of OS X, hit Command+N. You'll see a report with a lots of information about your networks, including all the other networks in your area. From there, you can follow these instructions to optimise your network for better performance.
Record Screencasts with QuickTime
The bulk of us don't need to record screencasts often. So, it's handy that the version of QuickTime included with OS X 10.6 and above does basic screencasting. With it, you can record your screen, voiceover audio and do minor edits. Open up QuickTime and click on File > New Screen Recording to get started. QuickTime isn't our favourite screencasting by any means, but it does the job for free.
Speak to Your Mac with Dictation
For years, dictation software was always pricey and didn't provide the type of system-wide support that most people needed. With the release of OS X Mountain Lion, Apple included dictation right in the operating system and it works well. Everyone talked about the new dictation feature when it was first announced, but over time it has disappeared into OS X a bit. If you haven't messed around with it in a while, head into System Preferences > Dictation & Speech to get started.
Digitally Sign Documents with Preview
Preview is one of the most underrated gems in OS X. Even though it's our pick as the best PDF Viewer and Editor, we tend to forget about all the different things it can do. Preview does everything that an average user needs a PDF viewer to do. You can sign PDF documents with your webcam, annotate files, fill out forms, and even insert new pages into a file. That's all on top of the handful of simple image-editing features that Preview has on top of its basic image viewing. If you haven't kicked Preview's tires in a while, take a look at everything it can do.
Invoke Dictionary with a Keystroke
Nobody wants to talk about how cool a dictionary is, but the Dictionary that's built into OS X is fantastic. The best part is that you can invoke the dictionary anywhere. Mouse over a word, then hit Command+Control+D to open up a popup window with a word's definition, synonyms, and more. You can also look up words using Spotlight or use text to speech to hear pronunciation out loud. It sounds silly, but Dictionary is awesome when you know how to use it.
Find Menu Bar Options Quickly with Help
The Help menu might not count as a tool, but it's still a handy and often under-utilized part of OS X. You can find any setting in an app in an instant with Help. In most apps, pull up the Help menu (Cmd+Shift+/), then search for what you need. From there, the Help menu will display menu bar options. This is useful when you're using an app and you don't know all the keyboard shortcuts for, or when you're using complicated software like Photoshop and can't find a particular menu item.
Add Handwriting Recognition with Ink
Unless you've hooked up a graphics tablet to your Mac, you've probably never seen Ink. Ink is OS X's handwriting recognition app that only appears as a preference pane when you connect a graphics tablet to your computer. Once it's set up, you can use it to write out notes or draw pictures. If you'd prefer, you can use it to hand write notes as well. Select the "Allow me to Ink in any Application" and "Handwriting recognition is On" boxes are checked in Ink's preferences. Then open up any program that supports text input, touch the pen to the tablet, and start writing. When you stop writing, Ink inserts the text you've written into the document.
Of course, with every iteration of OS X, lots of littlehidden tricks pop up as well, and each tool seems to get a little more functionality over the years. Some, like screen sharing and text expansion have become well-known over the years, but it's still nice to get a reminder that they're there.