Ear training
One of the best ways to know and understand the useful parts of music theory is to get yourself on a course of ear training. Using websites or apps specially designed for the task, you can quiz yourself on different note combinations and chords in quick quizzes based on sounds. Pretty soon, when having to think about the combinations of notes presented, you’ll start to absorb the different relative sounds, and back at your DAW, you’ll be able to reach for ‘that note in your head’ a lot faster.