Speaking as a primarily sub-type, but one who wants to please her partner but is getting very frustrated with it: think about what submission means to you/what you want from her as a top/Domme, and TELL HER. My idea of submission is very different from my partner's, so our first attempt did not go well. I did what I would have wanted/enjoyed, and pulled him right out of sub space. The problem is, this is the one area I cannot get him to communicate about. I would welcome a conversation, a letter, a fantasy story he wrote, or a story he found that gave me some clues. Hell, a list of likes and dislikes would help. I want so much to make him happy, but I cannot read his mind. Yes, I do see it as a service I can do for him, not that I hate it, but it is not my natural role. My only other experience with switching, my partner and I were almost identical as subs, so, with allowances for physical gender differences, I just treated him as I would want to be treated.
Good luck to both of you--you have encouraged her to join the Library, haven't you?