My T is very casual and so am I. I usually wear cords or khakis and a shirt and a cardigan/jacket of some sort. I got in this habit of wearing clogs to his office for when we did EMDR (I like the gizmos to be under my feet), and I find I still do that ("just in case" although we haven't done EMDR in a long time). I wear necklaces or scarves a lot. I sometimes wear a carved wooden heart on a chain if I'm feeling particularly "loving" or "open" towards T. I also have a necklace with a half dozen brass hearts and this serves the same function.

Other times I wear African beaded necklaces--he has commented on these a couple of times so I know he likes them.

I really like that T is so casual in his dress
Really I don't try to dress any way with T that I would not otherwise. Part of our work has been for me to learn to be "authentic."