A Free Fall is falling down without taking any damage.
Original Author: Pimgd
When: When falling down / getting down from high area
What: Falling down without taking damage
Why: Every hitpoint is vital in this game, because there is no way to get them back. When you have to escape, preventing a loss of 5 to 10 hitpoints can mean the difference between a loss and a draw, or even a win!
How: Instead of jumping off a building, walk off. This alone reduces the damage you take by 2 to 3 hitpoints, because you don't fall down the height of your jump. When you are nearing the ground, hit the jump key to jump mid air. You will jump as normal, and then start falling again. This reduces the height of your fall, and with it the damage. If properly executed, you take 0 damage.
Bonus: Besides just making for a quick escape, you can also take a potshot or 2 at your attackers! Hitting a falling target is very hard because it moves very fast. You could also perform a Bunny Hop at the end instead of a "normal" jump for extra accuracy, but you won't be able to get away as easily (since movement is limited during crouching).
How to practice: Go to Warehouse or Tower (SWAT), playing alone on a server. Climb the ladder, walk down, and try jumping during your fall. Try jumping as close to the ground as possible.