The following guest post is from Kenji Crosland, a writer for TeachStreet, a website that provides online and local classes including law classes and mac classes:
If you want to get your Mac black belt, you’ve got to learn your keyboard shortcuts. Knowing how to use CMD + C, V, X, and sometimes Y is a good start, but when you want to graduate to the big leagues you might want to get acquainted with the shortcuts here:
1. Quick Screenshots :: If you ever need to explain a computer procedure to someone else, making screenshots are a necessity. Macs are pretty cool in that you can use a keyboard shortcut to actually select the area of the screen that you want to save as an image. This saves you all the time it would take to crop the image in an image editor later. All you have to do is type in CMD + SHIFT + 4 and a marquee tool will appear right on the tool to appear on the screen like so:

2. Save some characters on Twitter :: You really want to put an ellipsis on your Twitter update, but you’ve ran out of room. The keyboard shortcut (OPTION + ;) will make the ellipsis appear as just one character. Very handy for when you’re running out of room!
3. Instant word suggestion + dictionary :: If you hit the F5 key in a text editor (when writing an email or blog post like this one), you’ll get suggestions for the word you’re trying to write. Like so:

And CMD + CTRL + D will look up the highlighted word in the system-wide dictionary app. What about you, what are your favorite mac keyboard shortcuts? Let us know in the Comments below…
Note: The awesome photo you see us taking a screenshot of above is by pardeshi.