You should be able to feel it, not count it.
Why not just listen to a lot of music in 6/8? The tempo is pretty obvious if one hears it first.
I disagree that you need to know what to listen for, as in you need to know it's 6/8. This meter will just feel like something that is uniquely 6/8.
in order to get the compound rhythm the teacher set my metronome in triplets. If I had done it on my own, I would have made a mistake and simply set a tempo of 6 beats
Barcarolles, Tarantellas.As an exercise, you could listen to "America" from West Side Story - it moves between 6/8 and 3/4, so you can try an spot the difference.