Shocking but true: if you're not using keyboard shortcuts and you work on a computer 8 hours a day for 5 days a week, you're wasting 64 hours a year! That's 8 whole work days that are totally lost because you're taking 2 seconds a minute more than is needed with your old-school, mouse-driven ways of navigation.
Yes, of course, there's an app for this. Brainscape offers a free app to teach you keyboard shortcuts right here, and you can put an download an app for your Mac desktop here that pulls up cheat sheets for each program that you're working on.
And here are cheat sheets that you can print out and keep next to you for reference.
And, some social media shortcuts:
Now - reclaim those 8 lost days and fill that time with something you love doing!