Sometimes the best tips are the simplest.
One of my favorite shortcuts is Ctrl+F. This is the keyboard short cut for the Find command.
Simple hit the "Ctrl" key and "F" key at the same time to open up a small search box in your document, webpage, or whatever is on the screen. Then, you can put in the word you are looking for. You have to type in the exact thing you want (this won't autocorrect or understand what you want like Google).
This is really helpful when you need to search long pages of text to see if they have what you need. It's also great for when you just know something is in a document but can't remember where.
I use Ctrl+F a lot when I am working with students to show them how to quickly "read" an academic article to determine if it's a source that will work for them. I also like how, depending on the program you're in, Ctrl+F will also show you how many times your search appears in the page. That's a great way to know the density and importance of a topic in whatever you're looking at.