A good RC is to pinch your nose and try and breath through it. If you can still breath through your nose, you are dreaming. This has been called a fail-proof RC. The beauty of this RC is that like your eye muscles, you have control over your diaphragm while you're dreaming too. So if you're dreaming and take a breath with a pinched nose, you will feel the breath going in and out through your nose still. It has worked well for me!