Do you expect reality check to work when you practice them in the waking life? Expectation is one one of things that makes reality checks work, other being awareness.
Before doing reality check in waking life, fully believe that you could be dreaming at that moment, put emotions into it as well, like "Wow, am i dreaming?", look around and try to find something out of place, even after not found still believe that you could be dreaming and do an RC, while fully expecting it to work, and additionally visualizing it.