I've known a number of non binary people in my life and I think single biggest conclusion I can draw from that is that non binary people are not the same. Like if Men fit in box A and women fit in box B, people really, really want nonbinary people to fit in a theoretical box C, and it just doesn't work like that. They are outside the boxes. They defy any simple categorization because they are not a third way of being, but every other possible way of being.
Being supportive of binary people is relatively simple, they have decided to sort themselves into one of the boxes that we have lots of experience interacting with. Being supportive of nonbinary people can be comparatively tricky, because you have to resist the urge to create box C and drop them all there. That's how we end up with various prejudices like "woman lite". Humans really, really like to categorize things. It helps us think. Unfortunately, sometimes it helps us think wrong.
If you have a non binary person in your life, I think it is important to take the extra effort to learn about them specifically.
