Slice the avocado open. Use a paring knife to cut around the center of the avocado, lengthwise. Start at the top and carefully rotate the avocado around slowly to move your knife completely around the pit. Once you've done this, gently twist the halves in opposite directions to "open" the avocado.
Remove the pit. Hold the avocado half that contains the pit gently on your work surface (not in your hand!), and use the knife to remove it . . . with a bit of force, start with your knife slightly elevated and chop into the pit. Twist the pit out by moving the knife that's attached to it about 90°. Then gently lift the knife up with the attached pit.Use a towel to remove the pit from the knife (not your bare hands!)
Peel the avocado. There are a couple of different ways to remove the avocado flesh from the skin. You can either carefully peel the skin off, or you can scoop the flesh out. (I much prefer to peel the skin off because it leaves it looking perfect, which can only be done when the avocado firm, but ripe. For the first method, place the avocado halves on a clean work surface, and cut about ¼ inch off the root ends. Then gently peel back the skin from where you've cut. With a perfectly ripe avocado, it will practically come off in one piece.For the second method, use a small to medium-sized spoon to lift the avocado flesh out. "Dig" the spoon directly between the skin and the flesh before lifting, so you can feel the back of the spoon directly on the inside of the skin. Go along the entire avocado half like this -- just like your loosening a cake from a pan.
Slice and dice. Round side up, slice the avocado to the desired thickness. From there, you can also cut it into any size dice you'd like.