1. Instead of spamming left-click to build a line or column of blocks, just hold left-click and right-click down at the same time to build a continuous stream. (Keep holding both keys until you want to stop building.)
Application: In Aloha urbantankfight (or any other map with hard to reach sniping spots), you can stand on a block and build a column to get to the top of the roofs in seconds, whereas it would take close to a minute with the traditional left-click spam.
2. To cancel out a part of the shotgun pump animation, quickly switch weapons and back, which will save you seconds. (Like the YY in COD.) I actually campared this version and the normal version, and you fire 6 shots about 2 seconds faster using this method.
Application: Makes shotgunning a lot more forgiving. Usually, you have to nail your first shot to kill a competent player. The time it takes to put in another shell can get you killed. With the pump-action cancel, you can either
a) miss your first shot and use the extra time to shoot another, or
b) take a shot at someone at a further distance to lower their health, so you can 100% take him out with the next.