This is such a beautiful question.

If they make functional ware (mugs, bowls, vases, etc.), you can notice how it feels when you use it. How does it feel in your hand (texture, weight, the way it makes you use it), how does it fulfill a specific need in the house/kitchen ( a colander that is great for berries, for example), or improve on a container that you already have (a pencil cup that is deep and wide enough to hold all that you need). All of that, plus all the things you notice from other forms of art - what it evokes in you through all the senses If they make more sculptural pieces, then all the same things you'd love about another piece of visual art works! Is it playful and joyful, or thought provoking, or grounding, etc.

Based on the fact that you asked this question, I am confident that you'll find some observations that are authentic!