Another great guide, Gab. I've been doing the "looking at the hands" RC in waking life for as long as I can remember. Oddly enough I never do this in my dreams though. The idea that I may be dreaming is usually enough for me to spot a distortion in the dream space before I even look at my hands. It works indirectly.

Being that many of my non lucid dreams involve fighting for someone else with weapons or even fighting dragons (!), there is too much risk in examining my surroundings or doing a normal reality check, so in this case if I find the dream a bit too unbelievable I will usually just block my airway without using my hands; it's sort of like a nose plug but blocking the trachea instead because it seems to take less energy to do so while being physically engaged. It is useful because you can perform it quickly without taking your mind off of what you are doing.