Tech Tip, Screenshot
I think one thing I was always frustrated with was the inability to capture things that appeared on your screen, or wanted to show someone what appeared on your screen but didn't know how to do that. One great thing I've learned is how to take a screenshot of your computer screen. All you need to do is press command + shift + 4 and you can drag and select which portion of the screen you'd like to screenshot. This has become very helpful to me in the past few weeks. Easily one of the most useful tech tips.