People make up many different reality checks that work for them. Some may work for you, others may not. The most effective reality check (in my opinion) is called the nose-pinch reality check. It's where you pinch your nose and try to breath through it. If you are awake you would be blocking air from coming in and wouldn't be able to breathe. If you were dreaming you would be able to. The thing about reality checks is you have to be aware while doing them. Don't just make it a habit that you do not think about. Also, you have to believe it will work. For example, with the nose-pinch check...BELIEVE you CAN breathe through your nose. If you assume you can't, then in the dream you won't be able to and won't get lucid. That make sense?

If you have any more questions, you are welcome to send me a PM!