I agree with the other posters on the importance of performing multiple reality checks. Like ThreeCat mentioned, the nose pinch test is not the most reliable, you may want to use a different primary reality check. I usually try to push my right pointer finger through my palm and then use the nose pinch test as a backup.

One trick I've learned to improve the success of reality checks is to do them with the assumption that you are dreaming. This challenges the basic human assumption that all experiences are waking experiences.

So rather than asking "Am I dreaming?", ask "How do I know I'm awake?"

It shifts the burden of proof on your mind to prove that you are NOT dreaming.

As for false awakenings, I agree with Travis. If you make it a habit to perform a reality check every time you wake up, you can turn false awakenings into extended lucid dreams.