The nose pinch test only fails if you are sick or something and have a stuffy nose irl. But I have rationalized the test failing before by saying "Oh, I must not have closed my nose completely and so air got through." One time I ran through the gauntlet of tests and they all passed but I wasn't convinced I wasn't dreaming. I focused on the weightlessness of my body and began to float higher and higher. I couldn't get down and woke up.
I try to be aware of what being in my dream body FEELS like. you could also try flying. float up or flap your arms like wings... that usually works for me.
Ahhh..there's nothing like that first hyper realistic dream. Even if you are lucid, you won't look at dreams, or waking the same again!