As a short follow-up to what dolphin wrote, you can also do daytime visualizations to help cement your intention to notice the dreamsigns in dreams: replay a recent dream in your mind where a dreamsign occurred: see yourself experiencing the dreamsign in the dream and recognizing it as a dream sign, tell yourself, "This means I'm dreaming. I'm dreaming! I'm dreaming!" over and over while you continue to visualize the dream scene with the sign happening. You're trying to create an association where experiencing the dream sign in a dream leads immediately to the recognition that you're dreaming.