Unlocking "Developer options" on an Android device is useful for many things. You can limit or stop transition animations for a snappier device, enable USB debugging to run fastboot commands, and more. But of course, the first step to making these tweaks is to unlock the hidden settings menu.
The screenshots in this guide from the latest build of Android—5.0 Lollipop—but the steps will be exactly the same if you're on an older build of Android.
Head to Settings and scroll down to the "About device" or "About tablet", then tap "Build number" seven times. You'll see a toast notification letting you know how many more times to tap.
Once you see the "You are now a developer" message, back out one level and you'll now have "Developer options" in the standard Settings menu.
Now go ahead and enable "USB debugging" if you plan to use fastboot commands or an automated tool like the Nexus Root Toolkit.