There are tried and true techniques, like checking your watch. When you're dreaming, it will show different times when you check it. So if you train yourself t

There are tried and true techniques, like checking your watch. When you're dreaming, it will show different times when you check it. So if you train yourself to check your watch for consistency (in your normal everyday life), your unconscious will continue the practice in your dreams, and you'll notice the inconsistency.