what people in canada do is, you try to sing a song from the first two notes.like minor 3rd would be the start of "Oh Canada!" (Canada's national anthem)perfect 4th would be the wedding songperfect 5th would be star warsperfect octave would be Somewhere over the rainbowetcand you do the same thing when it goes downwards. I'm not sure how much this helps musically, but it helps TONS for recognizing intervals for exams.
(But I still really wanna know what's with that G# tone!)
The trick is to listen to the intervals in the right way. How to do this is hard to explain. The brain is very susceptible in making a 'fallacy' and deciding an interval is bigger because the two notes were higher than the earlier ones.The main technique is to use intervals from well known songs. As a perfect 4th I use the bridal chorus from Wagner. Descending major third I relate to the popular doorbell sound. I must be a heretic for not relating it to Beethoven's 5th symphony.https://www.people.vcu.edu/~bhammel/theory/resources/macgamut_theory/songs_interval_recognize.html