Here's one thing that can help. If you are just doing mindless RC's throughout the day, they can become incorporated into your dreams, but you may not understand why you are doing them. Instead, when you practice RCs during the day, make sure to question reality along with it. For example, if I do an RC right now (I always try to breath with my nose plugged), I should also say to myself "How did I get here? Who have I talked to this morning? What else have I done today?"

Reality checks can fail during a dream, however if you ask those types of questions to yourself and you cannot answer them... then you are most likely dreaming.