Anchor intervals
In our tonal/modal music the (pure) octave and fifth play a key role in our orientation in the pitch space.
They are the intervals you shoud internalize. Develop a mental/aural representation that you can summon at any given moment.
Watch the explanation and demonstration in the VIDEO (submenu at the right).
Use the following exercise which contains a pedal (bourdon) as a tool for your orientation.
Do the exercise with different fifths as a starting point.