Anyone working with awareness and attention will probably tell you the missing components: intention and positive reinforcement. You can't directly make your awareness notice things. You can do two things which work indirectly. The first is cultivating intention. Remind yourself to notice your mental states whenever your conscious mind happens to remember to. Consciously check in on your mental state - again, whenever your conscious mind remembers to. This primes awareness - it tends to notice things that you previously consciously focused on.
The second component is positive reinforcement. Whenever your awareness works by drawing your attention to the trigger ("whisper"), pat yourself mentally on the back. This trains your awareness to notice this more often.